A large part of my high school class is on Twitter, but I can't stand to follow them. Most of them are blithering idiots, spewing incomplete, barely legible sentences about some stupid thing they've done.
I have tried to get people to use Path, but it hasn't caught. I see it as the replacement for Facebook. However, as other commenters have said, it would be impossible for Path to compete with Facebook because they don't have the sheer numbers of people that Facebook has. If I meet someone and want to continue communicating with them online, Facebook is the place to do that: I know that they're there.