Well, it might well be in classrooms around the world, and for many reasons. However, at the urging of fellow teachers, a tech guru (who is also a teacher) in Canada, has created a closed, safe system for education. It's called 'twiducate' the social networking program for schools. Teachers need to sign up in order to participate and students are given access only through their teachers. No student email is needed. Access can be via computer and/or cell phone.
Great blog post on 35 ways to use twiducate for deeper learning. Really a great way to bring the 21st century into the classroom! As this blog post says, the best thing about it is that it is free!