via arstechnica.com/

In the void between blogging and instant messaging, microblogging has emerged to provide users with yet another medium for electronic communication. Microblogging services, such as Twitter and Identi.ca, allow users to post short messages (140 characters or less) for their friends and followers. The technology offers a sort of universal back-channel for real-world events and helps bring Internet acquaintances closer together.

short description of twitter