Don't overlook Facebook's advantage of universal popularity. Everybody uses Facebook because everybody is on Facebook. That's a tough barrier for any new player to surmount.
Universal popularity isn't necessarily that useful. It really just matters that everyone you know is using it.
Just as Facebook used the collegiate social scene to grow, I think theres a lot of potential for a competitor to take a similar route. Find a relatively self-contained community and attack it. It wouldn't surprise me in the least if a Facebook killer eventually emerges from the university system just as Facebook did.
This is true, but it could work against the next gen. After all, who wants to be on the same network as their folks? That could make it uncool enough for other to look elsewhere.
Just as Facebook used the collegiate social scene to grow, I think theres a lot of potential for a competitor to take a similar route. Find a relatively self-contained community and attack it. It wouldn't surprise me in the least if a Facebook killer eventually emerges from the university system just as Facebook did.