I still think that the future of Facebook is data (not specifically picture data, that's just one piece). Advances in hardware and cloud computing have kick started an era where data mining and machine learning are pervasive in every field from pharmaceutical research to banking to sports and everywhere in between. Facebook is the single authoritative source for a whole bunch of personal data. People have started thinking about the basic applications for that data when it comes to things like online shopping (you're a 31 year old white male with an 8 month old daughter who likes rock and roll, so you probably want to buy diapers, zinfandel, and a radiohead album), but I think that lots of new interesting applications will emerge over the next several years that don't violate user privacy and will monetize well.