Today Bitly announced a new Bitly Labs project called Realtime, a service for finding the most clicked on Bitly links. Realtime, now in private beta, allows users to filter searches by social network, keyword, subject and more. For example, here are the results for a search for the keyword “startups” in technology on Twitter:

As you can see, it’s not perfect yet (why is that article on hidden Mountain Lion features being displayed on a search for startups?). But with Bitly’s traction in URL shortening, this could become the go to reference for trending articles and sites.

Bitly has been working on expanding its business beyond URL shortening in recent months and announced a new round of funding lead by Khosla Ventures earlier this month. In May the site launched a controversial redesign that recast the service as a bookmarking service rather than just a URL shortening service, and in January it launched an updated version of its enterprise dashboarding service.

But the really big idea the company has been floating is a real-time social search engine. since at least October when the company launched a social search engine beta for its enterprise customers. But the company made it clear that it had bigger plans for search. Realtime, which so far is available to non-paying customers, seems to be the first step in realizing those plans.