Launched in 2002 by three 20-somethings in a Calgary, Alberta, apartment,
StumbleUpon now has 2 million registered users drawn by its knack for finding websites that match their interests and those of others with similar tastes as they "stumble" around the Net.
Co-founder Garrett Camp (shown right), who totes around a mid-'80s Nikon F3 (yes, with actual film), came up with the idea as he was working on a master's in software engineering.
Frustrated as he tried to indulge his hobby online - "There wasn't a good way to find the best photo sites," Camp says - he tapped his own background in clustering technology. With coding help from Justin LaFrance and Geoff Smith, he created an early version of StumbleUpon. Having nailed the photo problem, the team quickly saw how the technology could click with all sorts of media.
In the same way that it matches users with like-minded websites, StumbleUpon's technology also pairs online ads with targeted demographics and interests. Now StumbleUpon is attempting to do the same for online video and video advertising. In December the startup launched StumbleVideo, a service that offers the closest thing to channelsurfing that you'll find on the Web.
Tell us what you think about StumbleUpon's model: Is it the next MySpace?
Funding: $1.5 million (Ron Conway, Mitch Kapor, Josh Kopelman, Brad O'Neill, Ram Shriram)
Headquarters: San Francisco
Employees: 12
Founded: 2001
Business model: Advertising, subscriptions
Bragging rights: Cash flow positive
Next up: New features like content controls and mobile video recommendations
Contact: Partners@stumbleupon.com 
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