Here's an interesting tool that was shared on educatorslog.in yesterday - a live discussion widget that can add a chat feature to any blog or website.
It is of particular importance to India, as it incorporates the Google's transliteration API for typing indic scripts for Hindi, Tamil, Telugu, Malayalam and Kannada. It requires one to be signed in with their Google (gmail) account to make sure that only the signed in users leave comments.
It integrates with Google Talk as well so that people can see their "friend" lists and "presence" cues (online/offline/busy/other status).
I can potentially see a class gathering online for a discussion around a blog post that a teacher has posted as an assignment, or even groups of friends meeting online at a designated time to discuss homework on a class blog. I guess blogs and blogging need to become part of mainstream educational use by teachers and students before tools such as this can be leveraged for collaborative learning.
A neat idea and potentially useful tool nonetheless!