MySpaceand FaceBookare the most popular with students. You do have to create a login and password to be able to see your student's pages. They may also have blocked access unless you have been invited to view their site. This helps them be safe, but on the other hand you don't have access to their pages also.

Nings have become popular in the Education world. You can create your own Ning space or join one like the
Macul Space