I just got into Twitter about a month ago and while I'm still not using it a lot, I think it has definite potential to be an effective communication tool.
I am currently using it mostly for announcements related to my school's chess club, of which I am the president and founder. Since many college students don't check their e-mail daily (which they SHOULD, since professors often use it to communicate) and not everyone uses social networking sites such as Facebook, I felt it would be a more effective communication method. I've also found some interesting entities to follow on Twitter, including one that deals with business and industry in my neighborhood.
I don't use it to let the world know that I am having spaghetti and minestrone for dinner or that I'm going to go to a baseball game with three of my friends. I find Twitter to be more of a business-related client (I'm sure some will disagree here, but since Facebook has feeds as well and is already more of a social-type site given its chat features, photo albums, and whatnot I think the two sites will eventually develop their own identities).
As a future educator I am already thinking about the ways Twitter could be used as a communications tool. It could serve as a way to remind parents that field trip forms are due or could be a "homework hotline", with reminders about upcoming tests and projects. Information about tutoring sessions or enrichment opportunities could be communicated, as could lists of recommended children's literature. There could even be a "problem of the day" that students could do at home for extra practice in math. Since I'll be at the elementary level I'd probably tailor this sort of information for parents and guardians (I believe Twitter has an age requirement of 13).
Is Twitter perfect? Absolutely not. There are problems with it much like Facebook, Bing, eBay, and Yahoo have problems. It will definitely endure its growing pains just like everything else did on the web (the "outage" a few months ago was definitely one of those growing pains). It may become an accepted part of culture much like AIM and Facebook have. The chances are good since it's all over the media and not in a negative light like MySpace, which is slowly dying.
As for this client--if I had a 68K on the web I'd definitely consider using it. Does anyone know if it runs on OS 9? Also, if there's a IIGS client, is there any chance a IIe version will be next?