StumbleUpon launches, raises cash from well-known angels

We’ve already mentioned StumbleUpon, the Web site that lets you stumble across other sites related to your interests. It has officially launched, after moving out to San Francisco from Canada. It moved here because it is a better place to do Web development, chief architect Garrett Camp tells us. It also helps that the company’s high-powered angel investors are here, he noted.

He said the angel round, raised really quickly in January, was above $1 million (he wouldn’t tell us exactly how much), and includes the likes of Web 1.0 angel impresario Ron Conway, Mitch Kapor, Stanford professor and early Google advisor Rajeev Motwani, Google founding angel investor and board member Ram Shriram and many more.

Updated

Camp said he came to Silicon Valley in the fall, and happened to be introduced to one of the angels. Before long, they’d put together a list of a dozen angels who were interested. “We went down the list, and we were only half way though it before we were done,” he said.

Surprisingly, Camp said the company has been “making money for a while.” How? It uses targeted advertising, so that a small number of the “stumbles” people make on the site are done by clicking on ads. The site has 1.5 stumbles a day, 875,000 registered users and nearly a third of those are active this week, Camp says (update: Camp says he got his figures mixed up, and that it’s closer to 1/4). That’s comfortably above the minimum of the now-proverbial 53,651. It’s apparently addictive, as the average user stumbles 22 times a day, the company says.

Camp says he’s aiming to make advertising account for one in 20 stumbles. He wants to charge people $20 for the right to turn off ads and get other features, though we’re skeptical he’ll get many takers on this front (update: we should have noted that he said he has already had about 3,000 takers on this). One of the features offered via a toolbar with Google and Yahoo, is to search results via those engines and be able to see StumbleUpon reviews about pages in those results.