This is my second entry since I forgot to save it the first time!!! I am learning.
I remember using UChat a few years ago for a distance ed class. Several classmates arranged a meeting time and chatted about some readings. I recall that it was fairly expedient and efficient. One use for UChat that I can see is replacing some conference calls with chat. It might be cheaper for one thing.
I am rather Zen and don't really like being connected all the time. That said, I prefer discussion boards to live chat.
Twitter is quite an enigma for me at this point. If one had a really specialized topic then it might be good to follow that. I think professors are challenged with all the technological devices and outposts that students expect these days. Seems like they will feel obligated to offer a class with bells and whistles just to keep students engaged. This is where the digital divide could really hamper student performance in some places. Then again, think of all the possibilities!!