Something's Happening Here

In the past week, the daily visitors at AVC have gone from an average of 10k per day to over 20k per day.

AVC visitors

While this influx of new visitors is welcome (welcome everyone!), it is also unnerving. Where is it coming from?

Well the answer to that is pretty obvious – StumbleUpon. Here are the top traffic sources to AVC for the past week.

AVC traffic sources past seven days

Typically direct traffic brings 40k visits per week. Readers clicking through from the RSS feed make up about 10k visits per week. Google search and Twitter each bring about 7,500 visits per week. StumbleUpon had been next on the list, bringing around 5k visits per week over the past few months. I have noticed StumbleUpon traffic growing pretty consistently over the course of this year.

But I've never seen a firehose of traffic and visitors like I've seen this past week from StumbleUpon. I'm not entirely clear what is happening here. But I hope it continues. More readers means more conversations and opinions and more friends. Welcome Stumblers.


Comments (Archived):

  1. zburt

    SU is such an underrated traffic source. 50% of’s traffic comes from SU.  140k visits last 30 days. NBD

    1. fredwilson

      i believe the ability to generate real, sustainable, high quality traffic is the source of enormous value on the net

      1. Diego Mariño

        I don’t see it that way. If you dig the data from your SU visitors, you’ll see a pattern: extremely huge bounce rate and a few seconds spent on your site.We ran a campaign on SU to test goal conversion, and it was low compared to any other source of traffic.SU brings you a lot of traffic, but engagement from their users is low (ATEOTD  they’re surfing the internet, not looking for anything concrete). 

        1. fredwilson

          that’s what i thought too but the SU visitors have a lower bounce rate than the other main sources. see the attached image

          1. Diego Mariño

            Ok… your blog is more engaging than our landing page 😉

          2. Morgan Warstler

            it would seem like time spent is more important here.

          3. Mike Kijewski

            That’s what I was thinking initially. But I bet having show up in your stumbleupon list repeatedly would lead to certain stumbleupon users spending more and more time on the site.I wish GoogleAnalytics would show you the standard deviation of the time spent on site. I bet you there is a bigger standard deviation for stumbleupon visitors, meaning that a sizable portion of them are spending significant time on the site. 

          4. ShanaC

            But they don’t appear to be coming back….

          5. Adrian Palacios

            Good point Shana…the frequency/recency reports in Google Analytics would tell us more about how often those visitors end up coming back.

          6. ShanaC

            So how do we qualify the traffic?

          7. Adrian Palacios

            When you say “qualify,” do you mean “decide whether or not this traffic is worthwhile”?

          8. ShanaC

            Yup. Just because there is traffic doesn’t mean I want it

          9. Adrian Palacios

            Okay, just making sure I understood. And I agree 100%: is the traffic worth it?It’s hard to qualify what traffic is the best traffic for–more visits per month, more “net promoters”, etc? I’ve always wondered what would be the top three key performance indicators as far as this blog.I guess I would start with what you suggested: see how many of these StumbleUpon visitors make the leap from the “New Visit” bucket to “Returning Visit” bucket. The Frequency report in Google Analytics would help determine how often these visitors come back…so, I would segment StumbleUpon visitors in this way, and see if indeed they are a) coming back, and b) if they do come back, how often. The assumption here is that Fred would like more visitors to be, putting it simply, “repeat customers.”What do you think?

      2. zburt

        There’s also increasing general interest in entrepreneurship; the general public sees entrepreneurship as a way to capture value (using your “net” analogy). Thus more SU traffic to AVC.

  2. Driftaway Coffee

    shocking. i’ve never understood who uses stumbleupon so much, compared to say facebook or twitter. but the numbers dont lie.

    1. fredwilson

      unless they are doing something funky. i don’t think so, but that’s one of the reasons i wrote this post. maybe somebody has some thoughts on that.

      1. JamesHRH

        I don’t think they are doing anything funky. Garrett has a history of seeing small cracks and then wedging them open. I never liked the initial idea of surfing the web by just seeing what others were looking at…… but the social recommendation position is a near perfect extension of that idea.He has collaboration aided UI in his DNA too – your kind of guy!The quietest high impact startup person at the moment (SU, Uber)?

      2. Katie Gray

        Google Analytics average metrics can be a little off, since GA measures time on site as zero if a visitor looks at only one page on your site. If you want to try out Paid Discovery and see what our metrics tell you, shoot an email to advertisers [at] stumbleupon [dot] com. Thanks for the shoutout, Fred!

    2. Jack K

      I think the biggest difference between SU and the other social services is that our users are all about finding things across the Internet that they find interesting (vs from the people they associate with). It’s more of an inward facing social experience, which leads our users to stumble to, on average, 300 different pages each month.The average monthly usage per user is about 7 hours, so we find that our users are engaging with the content that they like the most. We’re obviously not perfect, but for the content that gets rated, we see ~90% thumbs up ratings.All together, SU sends over 1 billion referrals each month. The coolest part is that you never know what will pop. It’s all up to the users to decide.

  3. Alan Mendelevich

    I haven’t seen this for quite some time, but 4-5 years ago I had some splashes of traffic like this from SU to one of my sites. I guess it works in waves and then it dies down over time. Kind of like something breaking through on HN, reddit, etc., but less predictable, harder to understand and a little more stretched in time.

    1. fredwilson

      like a gardener with a hose

  4. Alek Andreev

    Clever way to bring your attention to them!

  5. Max

    As far as I know, StumbleUpon sends more traffic in US than Twitter.  And this is certainly the case with my blog.

  6. RichardF

    they released an explore search box mid August – maybe people are searching on venture capital.  It’d be interesting to get some input from the guys at StumbleUpon

    1. fredwilson

      if they use their service, they’ll probably end up here at some point today 🙂

  7. thisheart

    On my site ( Stumbleupon is the second highest referrer.Though interestingly the SU users only generate a small fraction of the total pageviews.The total average pageviews per visit is 6.88, while for SU users it is 1.74.

  8. Tanay

    Is the entry page of the SU traffic the home page or is it particular posts? Maybe one of your readers recently submitted some posts to SU which got a lot of stumbles?

    1. fredwilson

      exactly, this post got 50k PVs last week from SU/a_vc/2011/07/explicit-groups-vs-implicit-groups.html 

  9. Ben Popper

    Was most of this traffic sent to one or two specific articles, or was it diffuse across A VC? Perhaps you gained a new reader recently who submits frequently to SU and writes good headlines and tags. As a result more of your material is being surfaced on their network. In my experience Stumbleupon is much harder to predict and influence than Digg/Reddit/Hacker News etc. 

    1. fredwilson

      50k PVs in the past week from SU to this page/a_vc/2011/07/explicit-groups-vs-implicit-groups.html 

  10. Powerball

    There was probably a news article realised during that period

  11. William Mougayar

    Stumble upon is the granddaddy of serendipitous content discovery. Most other recent “content discovery” schemes emulate what they do, one way or the other. In hindsight, it is something that Twitter could have done. It is a simple proposition: 1) tell me what your interests are, 2) tell me who your friends are, 3) give me feedback along the way. And leave the rest to SU to surface the best content when you hit it. (actually, Eqentia has a feature inspired by SU we call “Surprise me” where we analyze content flowing from your stream & recommend 30 new articles you haven’t seen before)Their recent escape from eBay’s thumbs has allowed them to resurface in full force, added by a flurry of social media integrated hooks and mobile Apps.I suspect much of that traffic is coming from mobile. They have iPhone, iPad & Android. Can you break-up SU’s traffic as mobile vs. desktop.

    1. fredwilson

      it is quite a success story as a spinout. kudos to them.

  12. bfeld

    MBA Mondays generated 20k page views recently.Take a look at your Stumbleupon search – pages that it finds that have meaningful traffic to you saved in “everyone’s favorites.”…

    1. fredwilson

      ooh. didn’t know about that page. it would be great to filter those search results by the past week to see what is driving the recent traffic

  13. Sebastian Wain

    Some years ago there were something called StumbleUpon effect, and it was different than other services. In my own experience just after a StumbleUpon effect we were in the delicious frontpage: StumbleUpon effect query on Google

    1. fredwilson

      seems like they are back

    2. Jean-Daniel Cryans

      some years ago (2007) something very important happened to SU… there might be a correlation here

  14. Gregg Grossman

    I’ve noticed in the past few weeks (maybe months)  getting a weekly email from them with recommendations. i’ve had an account for a few years … dont use the plugin or got to their site but i will usually see something worth checking out in the email. i think the email is something new their doing … maybe that’s the reason for the spike? could be that simple.

  15. Carl J. Mistlebauer

    Honestly, I never really understood the value of blogging, but now that I have played with it I have found that over 50% of the blog traffic is people looking for our big and tall shirts.Sadly, they all end up emailing me also and I have nothing to report, but I also realize that I probably should have sought funding by offering stock to our consumers; I would be oversubscribed right now….Oh, well, if it wasn’t for trial and error how would we ever learn anything!  🙂

  16. leigh

    I’ve noticed a bunch of people’s links on twitter have a stumbledupon header on them – makes me wonder if they’ve released an extension of some sort that shows up as any link on social sites being referred from them?  (that i wouldn’t call funky – if they are doing it i’d call it smart 🙂

    1. Mike

      Not sure if this is what you’re referring to but is a fantastic URL shortener. Along the same lines, someone else asked a question about how SU could be driving more traffic than Twitter. I wonder if one’s not leveraging the other.

      1. leigh

        exactly my thought just put MUCH better 🙂

      2. William Mougayar

        It seems to me they have a way to “claim” that URL higher in the food chain of sharing (my guess), because they know the minute anyone starts to share an article the first time, then it goes from there. Kind of like could have done, but didn’t do.  SU is a smart company by the look of it. They are doing a number of things right. I think I’m ditching all other “social media sharing” readers/services pertaining to general purpose/consumer oriented news.

  17. Alex Taussig

    Fred,I would be curious to know how time on site differs for your SU visitors. In my experience, they bounce more often and spend far less time on site.

    1. fredwilson

      See the image I posted in reply to Diego below

      1. Alex Taussig

        Thanks, Fred. Very interesting that the bounce rate is so low, but TOS is about where I thought it would be.

    2. Andy Bell

      We’ve got a site,, that generates loads of SU traffic. (Over 1m visits over the last year:, in our experience too it has totally been the case that they bounce more and spend less time on the site.

    3. Mark Essel

      I had the same experience on my blog.

  18. awaldstein

    Fred…regardless of source, these numbers from a visitor perspective are astounding. Congrats!Should be really interesting to see the streaming numbers that come out of your classroom/video MBA Mondays this Fall.

    1. fredwilson

      crossed 500k PVs this monthclose to 400k visitorsthat’s a boatload of people

      1. awaldstein

        You’ve cracked the code here and connected with a huge need for a new way to learn and engage.

      2. Mark Essel

        You’re gonna need a bigger boat 🙂

  19. Ronnie Rendel

    Guess it works both ways – just signed up to SU, cool stuff.  Am I the last guy on earth to join?

  20. Hrag Vartanian

    I’m glad to see this post because we were ourselves wondering what was happening with our blogazine ( and SU. In the last two months, SU has become a major traffic source and that was rarely true (with a few exceptions) before.

    1. fredwilson

      we need to know if the emperor has any clothes

      1. Hrag Vartanian

        Looking at the stats today, SU traffic has an average time on site of 4 seconds, while our other traffic is 2:08. So, it doesn’t seem like the visitors have a deep engagement with what they’re viewing.Though, I have personally used SU and discovered a few interesting sites.

      2. Vasudev Ram

        Ha, I love that emperor’s clothes quote and the story behind it (applicable a lot in real life, methinks and sees), though I didn’t really get what you meant by it in this particular context – maybe you used it in a somewhat loose sense. Anyway, here is the Wikipedia entry for the story:…See the section “Plot” at that page.

        1. Vasudev Ram

          P.S. I just read the background on how Hans Christian Andersen came to write that story – it may have been based on 2 incidents in his own life. See the section “Composition” at that page.

    2. ShanaC

      OMG, that is an awesome blog..

      1. Hrag Vartanian

        Thanks, that’s always nice to hear.

  21. ShanaC

    A) Hi NewcomersB) I’ve been hearing a lot about the stubleupon effect.  Though I have a stumbleupon account, the only person I really know who uses it is my brother.  What he seems to do is use it as a cross between delicious and twitter with his friends while skyping them.Though I don’t know why that would cause lots of traffic

    1. fredwilson


      1. ShanaC

        Things to not share with my brother…

    2. Mark Essel

      The folks at StumbleUpon would do well to listen to this type of usage. The increased engagement from skyping while stumbling may improve its perceived value. Lone stumblers may get bored (like I did). Groups of stumbling friends may go on virtual tours together, collaboratively curating serendipitous web discovery.

  22. ErikSchwartz

    I’m about to do what I hate (the plural of anecdote != data), but who uses StumbleUpon? I don’t. I’m not aware of anyone in my various peer groups who do.Are there SU demographics available?

    1. fredwilson

      the theme of this thread is “who uses SU?”

      1. Ryan from GroupTweet

        Anecdotally, the only person I know that uses SU is my little brother, a sophomore in college.  I know he doesn’t monitor many tech sites/blogs, use an RSS reader, or anything similar.  My lazy hypothesis is that the demographic skews younger, leaning heavily toward the youtube/facebook crowd. Honestly, I think Facebook (mainly facebook messaging), Youtube, and Stumbleupon comprised 98% of his online time while in High School.

        1. Kevin Morton

          My gut tells me the SU demographic skews younger too. I’m 21 and use it occasionally, and I have a large amount of friends who like it as well. It’s really a brilliant concept and service. Here’s categories that I’m interested in, here’s things I’ve liked before, now show me the web pages that others *with similar interests* have found the coolest. I’d be hard-pressed to find a better way to find a quick and unexpected source of inspiration.One reason it may skew younger might have to do with time availability. With a job and a family, time spent on the Internet is carried out with a specific purpose, I’d imagine, more often than if you were operating with less external responsibilities. Stumbling is a spontaneous stab in the dark–something one is more likely to do with a larger amount of wandering time on one’s hand.

        2. fredwilson

          that’s my take on SU as wellwhich is why it may not be a great fit with this blog

        3. Jack K

          Looking at the past month, our user base is consistently at about 75% in the 18-34 range. Skewed pretty evenly male/female: 54/46.

          1. Ryan from GroupTweet

            18-34 is a pretty big range. What % is 18-24?

    2. Cam MacRae

      The plural of anecdote is data, strictly speaking. 🙂

      1. ErikSchwartz

        There’s no scientific methodology in anecdote. Gathering data requires consistent methodology.Anecdotes only occur because they are amusing or unexpected. If something happens that’s expected and ordinary then it never becomes an anecdote. 

        1. Cam MacRae

          And yet Raymond Wolfinger’s brilliant rejoinder remains as I quoted above. Why it morphed into form so often seen on the web I do not know – as a statistician I find the original more compelling.

  23. jeffyablon

    Not just you, Fred.A report I read last week said that StumbleUpon now accounts for fully 50% of ALL social media referrals.And I expect that the report led to … more traffic at StumbleUpon.Thanks for sharing those details about all your traffic, though. A great data point!Jeff YablonPresident & CEOAnswer Guy and Virtual VIP Computer Support, Business Change Coaching and SEO Consulting/Search Engine Optimization Services

  24. Boris Fowler

    StumbleUpon has been a good source of traffic for us at Cayenne Consulting, but we are still trying to figure out what makes some blogs and posts more attractive than others. For a while we were seeing pretty consistent high results, but lately the amount of traffic has dipped. Anyone have any suggestions on how to remain consistent with the traffic numbers? 

  25. Rohan

    And I was thrilled when my blog’s Google Analytics average went up to 150, from 100. Got quite some catching up to do! ;)Congratulations on the numbers, Fred.And no idea on StumbleUpon. 

  26. Fernando Gutierrez

    I heard a few times Gary VaynerChuk (@garyvee:twitter) praise SU for how much traffic he had get through it, and not only in a distant past. Sometimes we forget that there are groups of people that keep using certain services even if nobody in the media notices.

  27. matthughes

    That’s surprising news about SU.Curious to know how much effort goes into SEO on avc?

    1. fredwilson

       not much

      1. matthughes

        I didn’t think so.Terrific news about all the new traffic!

      2. Garrett Smith

        I could help with that 😉

  28. Eric Leebow

    Yes, but they are picky about who advertises on it.  Great service, no doubt 2 letter names that are long with meaning and vision get remembered.

  29. Joe Lazarus

    StumbleUpon has been one of my secret weapons for traffic for some time… both in terms of free, viral traffic and in terms of paid placement through their ad product. I suspect their audience skews less techie and more mainstream, so they fly under the radar relative to Facebook, Twitter, and other industry darlings. 

    1. fredwilson

      and younger too

  30. David Noël

    We’ve seen a similar increase of referrals from SU to soundcloud.comWould really love to learn how SU works. Maybe @gmc can help.

    1. Jack K

      We put together a webinar here around how SU works and the free products we offer to help optimize the traffic: Hope that helps. I’d be happy to talk specifics if you have any questions. Just shoot me a note @thepolishjack:twitter

      1. David Noël

        Awesome, will check it out. Thanks, Jack.

  31. LE

    I’d like to see your logs and the IP addresses that the requests are coming from. Analyzing that would give additional insight. 

    1. fredwilson

      email me and i’ll authorize you to log into my account

  32. Michael Simonsen

    Every time I hear a “StumbleUpon generates huge traffic” story, I have the same reaction, “Who ARE these people?” I frankly don’t know a soul who uses SU to find new things. I know more people still reading Digg! I recently suspected it has to do with their URL shortener. They leave a spammy residue “toolbar” behind when you click on a link shortened with their service, and it redirects as fake pageviews on StumbleUpon. But that doesn’t explain the 74k visitors coming *all of a sudden* to your site. Nor does it explain the similar phenomenon of 5 years or so ago. SU would occasionally unleash a similar firehose (pre-ebay). For us none ever converted worth a damn. So I repeat, “Who ARE these people? Why do they only stay in AVC for 23 seconds?”Perhaps more importantly, “Are they worth anything?” Notably, no one has left a comment that said, “Hi Fred, yep, I just came from some SU link!” 

    1. LE

      We get the same type of artifacts with domain name hits. That’s why looking at the raw logs is a good idea. I’d be glad to analyze them if they are available.

    2. fredwilson

      great commentthat’s why i wrote the postwho are these people? show yourself!!!!!

      1. James Fuller

        Hi Fred, below I’ve raised my hand as a Stumbleupon user.I just thought about something that you might be interested in. One of the more frequent sites I’ve stumbled recently has been SoundCloud. This is one of the sites that get more interaction from me. You might want to ask them about their experience with Stumbleupon referrals.Generally, video(e.g. TED*, Youtube, and Academic Earth*) and audio(e.g. SoundCloud and 8tracks*) convert into user interaction and less bounciness in my personal usage.*Discovered these sites because of Stumbleupon.P.S. I can only see about 9 lines of text, when initially commenting, and can’t view what I’m typing past that. Using Firefox 6 on Vista SP2.

        1. fredwilson

          i believe david from soundcloud commented about that in this thread

      2. Apcrm

        Fred,, if it weren’t stumbleupon I would have never known your site

        1. fredwilson


          1. Edith Wiethorn

            Yes but – because of your post I signed up with Stumbleupon to try to see the pathway that brought 74k people here. The interest categories were generic & did not include categories such as or similar to: business, tech, trends, entrepreneurship, startups or finance. So let’s ask Apcrm how stumbleupon brought him here?

          2. BenHardy

            Most of those topics are offered -…If you didn’t select them at sign up you can add them from here :)…

      3. Quirky Jessi

        I showed up here via StumbleUpon myself! 

        1. fredwilson

          welcome to the AVC community. we are a fun group of people who love to talk about tech and the web.

      4. BenHardy

        Hey Fred, you can check out the Media Guide in the advertising help center for demo info on stumblers –

    3. James Fuller

      Hi Mike,I’m one of the souls who Stumbles around finding new things. I’ve been using it since ’06, liked ~12k pages and seen about 50k.I’m sure some of it is coming from the URL shortener, but I’ve never seen one of those links in the wild, nor used it.As for conversion, anecdotal evidence from my personal usage. It’s true I don’t convert on 99% of the sites I’ve seen. Only about 1% of the sites I’ve seen I’ve acted on site(e.g. comment, subscriptions, site-specific actions). Maybe 2-3% I’ve traversed further into the site. And maybe 2-3% get shared to at least one other network. I like about 24% of the sites I see on SU.My reason for stumbling is often just because it’s a quick laugh or as a quick informational search, that I bounce several times and compile them into a list to check later.P.S. I didn’t come through SU, but Disqus via Fred’s Friendfeed.

      1. ShanaC

        Hi and Welcome

        1. James Fuller

          Hi Shana,Thanks for the welcome. It feels weird as I’ve lurked over the community for at least a year, and maybe commented elsewhere on AVC, once or twice. I can’t slight you for not knowing; after all, it’s my own short-coming of being somewhat more passive in my interaction with this and most other sites.Well thanks again for the welcome, Shana.

          1. fredwilson

            i second that welcome James

          2. James Fuller

            Thanks Fred. Not just for the welcoming, but also for sharing your insights and fostering such an intelligent and inclusive community here on AVC.

      2. Mark Essel

        Glad to see you here Jimminy!It’s been a while since we met on friendfeed.There isn’t a better community than the commenters on AVC.

  33. Jason Steadman

    Wow I never knew stumbe could provide so many hits!

  34. Jesse Katz

    Hey Fred, if any of your readers are looking to dip their toe in the water with Stumble Upon, I run a deal site for SMBs.  This weeks offer is 50% off StumbleUpon advertising. It’s a great way to amplify the results of Stumble-worthy content.JesseFounder,   

  35. Rkbaker2

    I’m not going to pretend how traffic, referrals, etc work, but does LinkedIn use StumbleUpon for some of its email links, etc? I ask because I just “stumbled upon” AVC a couple of weeks ago when one of your posts were included in an LinkedIn venture-related news email…and LinkedIn doesn’t show up in any of your traffic/referral stats.

  36. Adrian Palacios

    Interesting, it looks like the past month has been quite a big one for StumbleUpon…their traffic was the highest ever in July 2011 according to http://siteanalytics.compet

  37. Adrian Palacios

    Fred, how would you feel about someone from the AVC community looking at your Google Analytics account to analyze the traffic–kind of a ‘State of AVC’ report. I’d definitely like the opportunity to do so.

    1. fredwilson

      do we get a post out of it?

      1. Adrian Palacios

        For sure! My email is brandingme [at] gmail dot com

        1. ShanaC

          can I help??? I love analytics

      2. Guest

        Hi Fred,I was wondering if you were still interested in a group post about AVC’s analytics data?

  38. Mark

    Apparently the roll out of the international panda update, AND an update to how google analytics calculates visits on the same day has been causing similar “growth in visits” for other websites as well. Info about the chance in how analytics calculates visits is here: http://analytics.blogspot.c…SeoMoz was where I first read about it and has more info around the issue.

  39. Eliz

    my SU traffic has dropped drastically in the last few weeks. hmmm…i think you might be getting traffic that is really intended for me :)has anyone else seen drops lately? My August SU traffic is about 15% of what it was in July.

    1. Eliz

      i liked and reviewed this post on SU. there were 2 views just now. let’s see what happens.

    2. fredwilson

      thanks for your audience 😉

  40. Ryanmatthewb

    Any correlation with increased mobile traffic or is it across the board?

    1. fredwilson

      good question. will investigate and report back

  41. Douglas Crets

    I think it’s your discussion of Google. 

    1. Robyn Tippins

      We see a definite spike in referrals from StumbleUpon when we cover Google or Microsoft. Oddly enough, no correlating spike for Apple mentions.

  42. howardlindzon

    I interviewed Garrett the founder  in Vancouver last week at Grow Labs… 

    1. fredwilson

      video imbed for the win. love it. totally awesome howard

  43. David Hornik

    I am not one to speak for my portfolio companies, so I will encourage the folks at StumbleUpon to give you some context on the growth of StumbleUpon traffic.  I was part of the investor group that spun StumbleUpon out of Ebay and the StumbleUpon team has done a fantastic job since that time increasing scale and engagement of their user base.  Your commenters below point out a few of the recent — link shortener that gives links a boost by adding them to the StumbleUpon recommendation trafficStumbleUpon Partnerships — LinkedIn and others have partnered with StumbleUpon to deliver great recommendations to their usersStumble Your Interests — rather than Stumbling broad categories, you can Stumble specific topics (I’ve seen AVC come up when Stumbling “Venture Capital” — I’m sure there are many other topics that trigger great AVC posts).The increased traffic you (and everyone else) are experiencing is the result of more Stumblers, Stumbling more.  It isn’t a trick.  It is just a great service with millions of users.

    1. Marc Leibowitz

      Hi, everyone.  I’m both a StumbleUpon user and part of the StumbleUpon team (insert Cy Sperling joke here), so I’m either doubly conflicted or doubly qualified to respond — you decide.First, many thanks to Fred for this post — at least as much for the (as-to-be-expected) excellent conversation it’s provoked as the merits of the write-up itself.  Fred, we’re huge fans of your blog, so for us this post is the equivalent of a Justin Bieber shout-out.Second, big thanks to David for the undeserved flattery of the work we’ve been doing to help people discover stuff they’ll love.  While we’re pleased w what we’ve accomplished so far, there’s still a ton of things to do.  We hope and expect our community of Stumblers will continue to demand big things from us. Third, in terms of why Fred experienced this surge in referral traffic, and why it appears to be more engaged than previous surges:  We’re constantly working to improve the quality of the content we index & the ways in which we recommend it (we’re focused on helping people find the best of what’s out there (“organizing the world’s *best* information”, in Google-speak), not providing comprehensive results like traditional search engines).  Over the last few months in particular — related in part to our Explore Box development efforts and the addition of several amazingly talented individuals to our already awesome team (myself obviously excluded :-)) — we’ve made significant changes to how we assess content quality, categorize content and recommend content.  The upshot is that folks who create legitimately good content (like what one finds on have started to enjoy more SU mojo than ever before, and the Stumblers we refer are connecting more meaningfully w the content they’re stumbled to.  So while everything David mentioned is accurate, I’d be remiss if I didn’t add that the underlying technology is simply getting better and better at detecting quality and anticipating what will resonate best with whom.Third-and-a-half: For one of our attempts to explain StumbleUpon referral TOS/BR, check out….Fourth, in terms of “who are these StumbleUpon users?”:  The StumbleUpon community has undergone a pretty dramatic evolution over the last 18-24 mos, from one dominated by 18-24 y.o. males to one that today actually skews slightly female and a bit older (I fit the “older” bill, but fall short on the “female” quotient :-)).  There are a number of reasons for this (which I’ll spare you here), but one consequence of this demographic shift is that there’s more sharing and rating activity per user (within StumbleUpon, women tend to share and rate more frequently than men) — which means we have more signals w which to make content recommendations.Fifth… OK, I could go on, but I won’t.  Happy to riff further on any of this stuff privately.  Just message me:  ml [at] stumbleupon [dot] com.

      1. fredwilson

        that is super useful info marc. thanks for stopping by and sharing it

        1. Marc Leibowitz

          Happy to wax poetic on this stuff anytime. :-)We’d love to collaborate w you on a deeper dive into your SU referral traffic, combining your data w ours.  Several of us are Google alums w reasonably extensive GA expertise — so might be able to extract some useful insights for us and your readers.  Holler back if interested….

    2. fredwilson

      brilliant spinout david. as i said in my tweet about SU today, it has its mojo back. i hope chad and steve can do the same with delicious

  44. Conrad Ross Schulman

    Are you using paid discovery? If yes, which package did you buy?

  45. rossdborden

    Not surprised. I’m also an avid user of SU, mostly because I know from looking at the Google Analytics of my own company, Matador, that SU delivers a TON of traffic, and using is understanding. I don’t use the service to discover things very often but I do “discover” things myself that I think will blow up, and they almost always do. We’re now doing over a million uniques/month now at Matador. Google organic is by FAR the biggest source, but SU is #2 – way ahead of facebook, digg, reddit, twitter or any other social sites. It’s a company and a product everyone in the content space should undertand – esp. if he/she wants to grow their audience and find new loyal readers and subscribers.

  46. Cathleen Rittereiser

    I’d recently noticed that StumbleUpon has been in the news more frequently, including a full post in the NY Times Bits blog on 8/17. http://bits.blogs.nytimes.c…   I’ve had an account for ages, but rarely used it.  Reading that post reminded me of the service and got me thinking to start using it again.  I’m guessing that a lot of NY Times readers may be sampling StumbleUpon for the first time or making greater use of it like I plan to.  

  47. Abdylas Tynyshov

    Unlike others StumbleUpon has a “multiplier effect” in their system, which in turn can be very effective form or traffic to your blog/websites if you have good content…

  48. mikenolan99

    I too am a SU user – mostly because my attorney’s daughter became their marketing director at one point (she’s since moved on.)I personally think the traffic increase is because of my speech in my MBA class – the one that ends with “everything you ever needed to know is right here…”

    1. fredwilson

      thanks for the plug!

  49. Vasudev Ram

    One data point: IBM developerWorks is using StumbleUpon’s URL shortener:!/devel

  50. Darren Herman

    It’s amazing how much traffic stumbleupon can drive.  It’s up there with the Drudge Report, yes, really.  We’ve also found that from a marketing perspective, paid stumbles perform well too.

  51. fredwilson

    but i play to pay