Facebook just launched Places, an exact ripoff of Foursquare. I’m not impressed with their vision – it seems as if they had insight into a future paradigm, realized it, and now don’t know where things are going, so they wait until other platforms are fully developed and then rip off their models. But they are all-encompassing, and it is my belief that people will choose a lean all-in-one (if it *really* is lean) more often than they will choose a smaller product.
One thing that Facebook should do (for its own corporate interests, not that this is necessarily a good thing for the interests of the open web): allow people to tag the web. See a friend in a YouTube video? Tag them. Someone writes a paper – tag them.
I’m very surprised that we don’t yet experience the web with social layers on top of it – chat rooms, comment boxes, ratings systems, link suggestions, friends’ browsing history, etc. laid above the plain ol’ web. I think Google is going to miss this boat and it will go to Facebook.