I think that was part of what was brilliant about facebook. They gradually went from restricted to Ivy league universities, to restricted to people with an .edu

I think that was part of what was brilliant about facebook. They gradually went from restricted to Ivy league universities, to restricted to people with an .edu domain to open to everyone. When I was still in high school I used a facebook clone by some local company restricted to high school students. The same company had equivalent sites for university students and the general public, once facebook became generally available outside the US they rapidly lost market share. At that point facebook was still considered "cool" in my social circle because it was the place where american university students hung out.