According to Bokardo,
So many students use chatting tools and social networking sites that MSU is even considering phasing out the #1 internet tool of the last 30 years: email accounts. Because students are online all the time and messaging through other means, there is little need for personal, school-based email accounts. Everybody simply uses the built-in tools in the virtual spaces they inhabit.
Now it is true that users of social software use social features like messaging often. However, I think one goes too far to assume that school-based email accounts are in danger of going unused now that Facebook is here. When I was in school (a whole two years ago) I used my .edu address for important academic and professional communication, and I can’t imagine that many students would want to use their Facebook identity for either of those purposes.
That being said, conversation happens where people are. People who hang out at bars talk at bars. Even though messaging at Facebook is asynchronous, people who hang out on Facebook talk on Facebook because the Facebook gives them context to communicate. I think that email is thus seen as a more intimate form of communication than Facebook messaging because you’re taking the conversation out of the Facebook context.