"Twitter is a free social networking and micro-blogging service
that enables its users to send and read messages known as tweets.
Tweets are text-based posts of up to 140 characters displayed on
the author's profile page and delivered to the author's subscribers
who are known as followers. Senders can restrict delivery to those
in their circle of friends or, by default, allow open access. Users
can send and receive tweets via the Twitter website, Short Message
Service (SMS) or external applications.
" [source: Wikipedia
It is basically a way to publicly broadcast text messages. Consider
it a text message that people can read publicly, or a post that is
forwarded to your mobile phone.
BApk organizers, moderators and coordinators are going to post
updates about on- and off-line activity, and, if you register your
device, you are going to be updated in real time.
Articles that help you GETTING STARTED:
For Blackberry, we just started using Übertwitter (http://www.ubertwitter.com
On desk/laptops some are using Tweetdeck (http://www.tweetdeck.com/beta/
Check us out here: