What Is StumbleUpon? The History and Timeline

StumbleUpon is a ‘discovery engine’ that helps users find the best of the web according to their interests and preferences.

It is all about helping its members (Stumblers) find new content that’s interesting to them. It can be useful to think of StumbleUpon in comparison to Google; just as Google has the practical ‘search’ part of online behavior more or less sorted, so StumbleUpon has the desire for ‘discovery’ pretty much wrapped up.

There are several different ways to use StumbleUpon, but the most common is via a browser toolbar.

Hitting the ‘stumble’ button on this toolbar will bring up a web page that has been submitted and rated by fellow Stumblers. The actual submission and rating of content also can be done via the toolbar.

Content that gets a lot of “thumbs up” will be shown to lots of Stumblers; content that either doesn’t get voted for or receives thumb-downs will be shown to fewer Stumblers. The profiles of the users that either thumb content up or down also effects how well the submission does.

Newly submitted content passes through the “classification engine” before it is entered into the system. This is simply a manual categorization of content using a compulsory category (from a drop down list of more than 400) and optional tagging. Typically, this process occurs via a pop-up box, which also encourages you to add a review of the content.

The StumbleUpon recommendation engine is powered off three sources of information, as the StumbleUpon site puts it, “a combination of human opinions and machine learning”:

• a Stumbler’s settings — users select categories they’re particularly interested in, such as photography or fitness;
• a Stumbler’s history – the StumbleUpon engine will look at the kind of content a Stumbler has liked or disliked in the past to inform further recommendations;
• friends and peers – StumbleUpon uses the behavior of other Stumblers who have similar preferences and/or stumble history to improve their recommendations.

StumbleUpon describes this process as “collaborative filtering.”

The more a Stumbler uses StumbleUpon, the more precise and useful the recommendation engine. StumbleUpon also records a user’s likes and dislikes in order to build social networks of like-minded web users, which can then feed back into the recommendation engine.

Just as in other social networks, some members are more “powerful” than others. In StumbleUpon’s case, the power is derived from an undisclosed algorithm but has to do with number of submissions, fans, ratings and reviews. This means that a thumbs-up from one individual can carry more weight than the same kind of approval from another.

Where It All Began

StumbleUpon was founded in November 2001 by Garrett Camp, Geoff Smith, Justin LaFrance and Eric Boyd. The four men decided to start a company together before they knew exactly what they wanted to do. Five or six ideas were tested but StumbleUpon became the clear winner within months.

Camp is StumbleUpon’s CEO and has been involved in the direction and growth of the company since day one. He earned a master’s degree from the University of Calgary in software engineering researching “evolutionary algorithms, knowledge retrieval and web usability.” Smith is the company’s CTO.

The team worked on StumbleUpon for nearly five years before Brad O’Neill, a Silicon Valley investor, happened across the site and persuaded two of the four founders to move to San Fransisco (LaFrance stayed in Canada). Once based in the Bay Area, the company raised another $1.2 million via other angel investors, including Ram Shriram of Google and Mitch Kapor of the Mozilla Foundation.

StumbleUpon’s Growth

The domain name www.stumbleupon.com was registered on Nov. 5, 2001. The site started out as a trial product but attracted 10,000 users in its first year. The founders of StumbleUpon have talked about how they weren’t in any rush to grow the community as they worked on the toolbar and recommendation engine, often working from the feedback of its committed members. As Garrett put it: “At the beginning we were less worried about getting users than we were about fixing issues and bugs.”

By the time Camp and Smith moved to San Francisco in 2006, StumbleUpon had 500,000 members. Following a post-VC funding “launch” in May 2006, the site moved into the mainstream and started to gain coverage around the web. By July, StumbleUpon had 1 million users and by December, more than 1.6 million registered members.

This pattern of growth continued: 2 million registered users in 2007 and by the end of 2009, more than 8.7 million members. The StumbleUpon homepage features a constantly updating number of members — it’s at about 13.5 million at the time of this writing.

StumbleUpon’s massive growth can also be measured in the number of “stumbles.” In May 2008, the site reportedly reached its 5 billionth ‘stumble,’ more than 1 billion of which occurred in the first five months of that year.

A tweet from Camp earlier this month declared that StumbleUpon had even surpassed Facebook as the No. 1 source of social media traffic.

Though the StatCounter chart he referenced has since changed and shows Facebook at the top again, it’s worth noting that StumbleUpon is the only social media site that comes close to Facebook for traffic generation.

StumbleUpon Timeline

2001 – The domain stumbleupon.com was registered on Nov. 5, 2001. The site grows gradually, with its founders spending four years improving its service.

Early 2006 – Angel funder Brad O’Neill discovers the site and starts investing. He also persuades two of the four founders to move to San Francisco.

July 2006 – StumbleUpon introduces its first public version for Internet Explorer, taking its service into the mainstream. There is much excitement over the expected exponential growth of the site: “With the release of the Internet Explorer extension, millions more can start discovering interesting sites they never knew existed.” (Garrett Camp on DesignTaxi)

Mid-2006 – Although targeted advertising has always been a part of StumbleUpon, 2006 sees the bar substantially raised. The new advertising engine allows marketers to pay to appear as a recommended stumble, and Camp states that he expects 1 in 20 stumbles to come from paid submissions.

December 2006 — StumbleVideo is launched. This is a service that allows members to stumble through videos aggregated from highly rated sites, including CollegeHumor, DailyMotion, FunnyOrDie, Google, MetaCafe, MySpace, Vimeo and YouTube.

April 2007 – StumbleThru is launched. The service allows toolbar users to stumble content from specificsites, including YouTube, The Onion, Flickr and Wikipedia.

May 2007 – eBay buys StumbleUpon for $75 million dollars. According to TechCrunch, “eBay says StumbleUpon fits well with their ‘goal of pioneering new communities based on commerce and sustained by trust’.” There is much speculation over what eBay will do with the service; most are anticipating some kind of ‘StumbleUpon Shopping,’ but nothing of the kind materializes.

June 2007 – StumbleUpon introduces a Facebook application that allows users to display their recently thumbed-up stumbles on their profile page.

July 2008 – StumbleUpon experiences a large drop in traffic. According to Comscore, in one year, StumbleUpon’s July visitor numbers dropped from 4.4 million to 1.3 million, and from 31 million page views to 25 million page views. However, the number of registered users on the site continued to rise. CEO Garret Camp says on TechCrunch that this has occurred because “users tend to Stumble without returning to the site’s homepage, so their hits aren’t recorded.”

September 2008 – Less than 18 months after eBay acquires StumbleUpon, the site is up for sale again. eBay hires Deutsch bank to find a good buyer and there is much speculation about whether the same selling price from a year and a half earlier will be reached.

Sept. 30, 2008 – StumbleUpon launches its web-based browser toolbar, which allows users to use the service without installing anything on their computer. The release comes at the same time as announcements of StumbleThru partnerships with HuffingtonPost and HowStuffWorks.

April 2009 – Garret Camp, Geoff Smith and a few other investors buy back StumbleUpon and declare it a startup once more!

Oct 28, 2009 – The StumbleUpon blog introduces the “New StumbleUpon,” which improves the usability of the web-based browser toolbar and makes several noteworthy changes to the interface. The following major enhancements are listed on the promo page: Stumble ‘before’ you sign up, Fresh content on all category pages, Stumble on the go, save it to your profile and Enhanced User Profiles.

March 2009 – StumbleUpon launches su.pr, a URL-shortening service similar to bit.ly and tinyURL and to Digg’s (now-defunct) DiggBar. When a su.pr link is clicked, the web-based StumbleUpon toolbar will appear, allowing users to like, dislike, stumble, favorite or comment on the web page.

February 2010 — Marc Leibowitz joins the StumbleUpon team from Google as the new VP of Business Development and Marketing.

Mar 10, 2010 — StumbleUpon launches a new advertising system, which improves the tools and metrics available to marketers. Perhaps most importantly, the new ad dashboard shows both paid and free stumbles gained from a StumbleUpon campaign.

May 2010 — StumbleUpon shares some numbers on its blog to do with its growth and ongoing popularity. These include: a 118% growth in active users since 2009, more than 100,000 StumbleUpon fans on Facebook and 5.4 billion recommendations delivered since April 2009.

June 2010 — StumbleUpon reaches its 10,000,000th member and holds a party to celebrate.