Friendica is a distributed social network application. Which allow users to connect with others via their own Friendica server, but may also fully integrate contacts from other platforms including Twitter, diaspora*, Pump.io and StatusNet into their 'newsfeed'. In addition to these two way connections, users can also use Friendica as a publishing platform to post content to Google+, Google Buzz, WordPress, Tumblr, GNU-social, and Libertree. The list of supported networks is growing. In addition, e-mail contacts and RSS feeds can be integrated. ... More Info »
The developers argue that decentralization on small servers is a key condition for the freedom of users and their self-determination.
There are two options to choose from to try Friendica. The first option is to join one of the already installed Friendica server listed at http://dir.friendica.social/servers The second option is to install your own server at https://github.com/friendica/friendica/releases Both options are fully free.
Friendica runs on commodity hosting platforms powered by PHP/MySQL/Apache. If you can install Drupal or Wordpress you can probably install Friendica. A single Friendica installation supports up to several thousand members.
Every Friendica installation can connect with any other to create a social network without limits. And one that nobody can own or control.