Instant Messaging

I've used instant messaging before (been a few years), and while I can definitely understand its usefulness at home when communicating with friends and whoever else, I'm not sure how "useful" it could be in a library setting. Perhaps librarians could schedule virtual book discussions, during which all participate via instant messaging. I wonder if this type of thing has been done already, or how it would go if tried...In any case, I've used Yahoo! instant messaging before, but this time, since I use gmail now, I downloaded the google talk application (jdk0030), but they all are pretty much the same, I'm sure. It does seem, however, with Facebook, Twitter, and other social phenomena (such as cell phone texting) which have arisen since instant messaging became so popular years ago, that fewer and fewer people would be as actively engaged in instant messaging as in these newer web 2.0 marvels...I haven't seen any numbers to support that theory, but who knows?