(to preface, I think the header they put in for your message was "My Idea", hence my response in the first line):
or even-- something of a lack of an idea. Though I understand the need to expand, add new features, widen the breadth and appeal of the site, I find myself less interested, the bigger facebook gets.
What I liked about facebook in the first place was, a directory/public space of all sorts of people that I see at college, as well as a way to keep tabs ro get in touch with people who I used to know from high school. And taht's pretty much it, and that's what I value it for now. I use groups, friending, walls, and haven't made use of things like notes or news feed much, except for sake of satire and parody.
What defines facebook is that it is THE social networking site for college students. Myspace.com is generic, broad, big and ugly. I would suggest that instead of trying to expand in a direction that, like it or not, will seem like Facebook is trying to become myspace-- why not try to expand INWARDS. Focus on what sort of social networking tools are most useful for college students and only college students (or high school, if you're into that, but I was never involved in facebook in high school, so I wouldn't know).
I can't think of ideas of "expanding inwards" off the top of my head, but I trust that you can. Know your market, know what you're good at, stick to that, and continue to improve upon facebook as a college directory and social networking site. There is no website better this for that exclusive purpose.