Twitter has been something for me that has fluctuated between being a useful academic resource and another waste of time/tool for procrastination.
What category it falls under definitely depends on what you make of it. For example last night I was using Twitter to follow a Red Wings hockey game while in the Library and I used it as an escape from doing my reading for class the next day. I had become hooked on the updates from the Red Wings Twitter feed as my team mounted a comeback, which led to overtime loss.
Than there are times like this afternoon where I opened up my twitter and looked at what Marc Lynch and Andrew Carvin were saying about what is going on in Libya. This led to me reading an article by Lynch posted by Carvin on Twitter about the war that is on going in Libya, and this page included in an extended interview that Lynch gave to NPR on the issue that provided greater detail on the issue.
These are two polarized ways in which Twitter can be used.