From EduTechWiki - Reading time: 1 min
“Is a free social networking and micro-blogging service that allows users to send "updates" (or "tweets"; text-based posts, up to 140 characters long) to the Twitter website, via SMS, instant messaging or a third-party application such as Twitterrific or Facebook.” (Ramsden, 2008/Wikipedia).
Daniel K. Schneider thinks that twitter replicates very much what people do with SMSs and instant messaging. Therefore one could use this technology to implement mobile learning/ubiquitous learning type of things, e.g.:
Furthermore, this kind of microblogging
Since messages are very short, they also can be sent from a cell phone.