StumbleUpon is an Internet community that allows its users to discover and rate Web pages, photos, and videos. It is a personalized recommendation engine which uses peer and social-networking principles.

Web pages are presented when the user clicks the "Stumble!" button on the browser's toolbar. StumbleUpon chooses which Web page to display based on the user's ratings of previous pages, ratings by his/her friends, and by the ratings of users with similar interests. Users can rate or choose not to rate any Web page with a thumbs up or thumbs down, and clicking the Stumble button resembles "channel-surfing" the Web. There is also one-click blogging built in as well.

Toolbar versions exist for Safari, Firefox, Mozilla Application Suite and Internet Explorer, but also works with some independent Mozilla-based browsers.

eBay acquired StumbleUpon in May 2007 for $75,000,000.

History

StumbleUpon was founded by Garrett Camp, Geoff Smith, Justin LaFrance, and Eric Boyd during Garrett's time in post-graduate school (in Calgary, Alberta, Canada). The idea of creating a company was established before the content: of the five or six ideas for products, StumbleUpon was chosen. Garrett describes in a BBC interview the moment for him in which he felt the company had really taken off: "When we passed the half a million mark (in registered users), it seemed more real."

The popularity of the software attracted Silicon Valley investor Brad O'Neill to take notice of the company and assist with a move to San Francisco, as well as bringing in subsequent fund-raising totaling $1.2 million from other angel investors including Ram Shriram (Google), Mitch Kapor (Mozilla Foundation), Josh Kopelman (First Round Capital), and Ron Conway. Garrett Camp and Geoff Smiff now reside in San Francisco, where StumbleUpon is headquartered.

Service details

StumbleUpon uses collaborative filtering (an automated process combining human opinions with machine learning of personal preference) to create virtual communities of like-minded Web surfers. Rating Web sites updates a personal profile (a blog-style record of rated sites) and generates peer networks of Web surfers linked by common interest. These social networks coordinate the distribution of Web content, so that users "stumble upon" pages explicitly recommended by friends and peers.

Users rate a site by giving it a thumbs up, thumbs down selection on the StumbleUpon toolbar, and can optionally leave additional commentary on the site's review page, which also appears on the user's blog. This social content discovery approach automates the "word-of-mouth" referral of peer-approved Web sites and simplifies Web navigation.

Stumblers also have the ability to rate and review each others' blogs and join interest groups, which are community forums for specific topics. Users can post comments in the manner of a discussion board in these groups and post links to Web sites that apply to the specific topic.