One of the most powerful features of Twitter and the “What are you doing now?” function on Facebook is the concept of real-time updates. Knowing what your friend’s cat just ate for dinner is a complete waste of time…but in class, having people post questions, comments, links to relevant material, etc can foster a really dynamic, interactive environment. The goal is to reduce the one-way stream from instructor to student. What you do is set up a separate overhead screen that shows the Twitter stream so everybody can see updates…and then respond or bring it up in class. Very interesting.