I have had a twitter account for a while, though I don't really use it much. I am not very interested in people who comment on being tired, or driving home from work, or eating a ham sandwich, or this or that. I am a follower of several tweets related to my work. I tend to tune in when there is something newsworthy that I know people/organizations will be tweeting about. I never tweet myself.
For Thing 21, I explored two Twitter-related sites that were new to me. The first was Twittervision.com, which is just plain fun in a laid back, nothing else to do, kind of way. The other site I looked at was Search.twitter.com, which actually proved to be useful. I was able to put in some current events and find tweets related to them from a variety of sources. I will probably use this in the future.
I wouldn't use Twitter in my classes. The format is too limited for connected thoughts on an issue. I can see how it is useful for updating friends and family on an adventure like a project term trip.