Graph Search...is a dramatic new way to browse Facebook. But its implications spill over its rivals—which companies lose the most?

It's hard to give Facebook's new search engine a fair appraisal, because it's not really a search engine in the same way Google is or Yahoo was. It's also in beta, out of reach for almost all of The Book's billion users. So what is it, and, more importantly, what does Facebook want its search to be? The simple answer: A murderer of all Internet competition. But how that'll be accomplished is murky.

Still, Facebook search means a billion people will have good reason to reconsider using other things. What other things? [Google, Yelp, Foursquare, New MySpace, OKCupid]