The article by Dave Parry says:
I thought I would explain how I use it, specifically for academic related uses, and teaching.
Includes a really interesting observation on the way that learners used Twitter for classroom chatter.
The first thing I noticed when the class started using Twitter was how conversations continued inside and outside of class. Most of these conversations were not directly related to class material, but many were tangentially related. Because the students had the shared classroom experience when something came up outside of class that reminded them of material from class time it often got twittered. This served as a reinforcement/connection between the material and the “real world.”
The whole article is well worth reading if you are wondering about the academic benefits of Twitter.
In case you are still wondering what Twitter is…
One thing about Twitter is that you need to “do it” to really understand it.
Many of these ideas would also work for Jaiku (and in some cases with the threaded commenting could work better).