This article also has an interesting view on how twitter can be used as a tool to help students. It talks about posting homework and also having live streams in class to ask questions and talk about when they are confused.
I found this in the comments of the last article I posted. The students of William Paterson have used twitter to reach out to incoming freshman and give them advice. I thought it was an interesting twist on how twitter can not only be used as an educational resource but also as a way to better your study habits.