My strong suspicion is that the educational impact of Twitter will, largely, be like text messaging: learners might use it a lot as part of what TRAC would categorise as administration in support of teaching, but it’s not likely to be a major new pedagogical medium. Sure, it’s many-to-many, but it’s many-to-many broadcast, not many-to-many interactive. Great for learning about what your mates are up to at the moment but not so helpful for learning about tensor fields. But I’ve been wrong before.
So, I hereby coin the word Twittorial – or perhaps less trademark-challengingly – twittorial, to meaning an educational experience mediated or strongly influenced by microblogging. Not quite sure what an effective twittorial would look like, although I suppose you could turn the concept slightly on its head and use it to describe a Twitter-related HOWTO.
If the word ever takes off, you saw it here first. I can’t find a single mention in search engines. I offer it up freely under a Creative Commons attribution license (the new name for academic good manners): do what you want with it but make it clear where you got it from.