Identi.ca is a micro-blogging service based on the free software StatusNet.

If you register for an account, you can post small (140 chars or less) text notices about yourself, where you are, what you’re doing, or practically anything you want. You can also subscribe to the notices of your friends, or other people you’re interested in, and follow them on the Web or in an RSS feed.

Identi.ca is an Open Network Service. Our main goal is to provide a fair and transparent service that preserves users’ autonomy. In particular, all the software used for Identi.ca is Free Software, and all the data is available under the Creative Commons Attribution 3.0 license, making it Open Data.

The software also implements the OpenMicroBlogging protocol, meaning that you can have friends on other microblogging services that can receive your notices.

Website:  Identi.ca