I would add that I don't agree with all of Brian's points. Particularly, the idea that "the future of search is social" is way overblown. Generalizations like that don't take into account

* that humans are all different and no matter how "friends like us" we have, no one's the same and no one has the same interests as me -- ultimately, I may be interested in what my friends like, but I want what I like

* there are many kinds of (and reasons for) searching, and not all lend themselves to a social element

Still, a good read.

I would have to agree with MattMcGee and say that Facebook is a long way from becoming the main player in terms of search. Fact is Facebook cant do to many things all at once and is and always will be a social network. True social networks are a part of search results but I think all we might see in time is Google taking into account how many 'likes' a company gets on Facebook and then that will have an impact in the search ranks.

Also you need to note that Facebook still doesnt really have a slippery business sign up section and you can tell when you are inputting commercial details that it still feels like a social network and not a commercial network.