The real question which most people fail to ask themselves is are those purposes for connecting enduring. Initially it will always seem so to most people, but what about next month or next year when you've graduated or left your job. Those purpose that existed before will no longer be there. Will people be constantly finding new purposes to stay connected when you no longer desire to go to party's or have a project to complete. From that point of view its no different in the college era as much as in the...well how should i put this...real life era.
But thats the long term view of the utility of facebook which most people cannot see.
quite surprisingly, my mom joined facebook last week. she friended me and put up family pictures. i've had several friends from college and that i've met since message me about those pictures -- in a very real sense, it's joining my personal networks on many levels and allowing people to stay in touch with me and for me to stay in touch with them more easily.