Free social bookmarking service AddToAny just turned a profit – right before it’s having its 5^th anniversary this week (same age as Twitter!). The AddToAny button is one of the most-used  widgets on the web – and the most distributed one from a bootstrapped start-up. It handles over a billion widget loads and millions of shares a month from over 90 million visitors, but the start-up is probably not taking its outlook as seriously as other emerging start-ups (financially, in AddToAny’s case.)

“Founder Pat Diven II says he has never felt the need to raise outside funding, although he reckons it might be fairly easy to secure financing if he wanted to. That said, he started AddToAny as a side project and, going forward, wants to keep things simple and stable first and foremost.”

This strategy has evidently paid off for the start-up, which competes with some of the biggest venture-backed social bookmarking companies on the web. According to Diven, there have even been multiple serious buy-out offers throughout AddToAny’s 5-year existence – all of them turned down. These decisions seem to have paid off as well– after all, AddToAny have a very bright outlook selling big data.

The start-up, as well as its competitors, which include the recently funded StumbleUpon and Reddit (who surprisingly doubled its programming team a short while ago), make money by selling anonymous shares of big data. This helps advertisers to optimize and increase the relevancy of their ads, and Clearspring’s AddThis is also a member of this club, all geared up for 2011. Using metrics to assess market conditions and optimize ad campaigns is one space featuring lot of demand, and consultation firm Deloitte even included it in its study as one of the top 10 trends CIOs should address this year.