Earlier quoted context omitted.
The future of Facebook is not targeting you on 'a social network', its opening up an ad-sense competitor and targeting you on any website - with your personal information. The like and connect buttons are just the first step. With that in mind it sounds like a good deal to me.
So why would people want to be Facebook users? What value are they getting besides targeted ads? I find it amusing to see people trying to imagine theoretical ways Facebook could earn income to justify their insane valuation. It is essentially the very definition of speculation. A prudent investor wouldn't touch that shit with a ten foot pole.
Erm... people like talking and interacting with their friends, and facebook makes that extremely easy?
Ways it could make money in the future - since it could act as the online identity of a substantial portion of internet users, and gets the attention of a significant portion of those daily or weekly, there are a hell of a lot of ways.