It is developed by many different people from all over the world in their spare time. There is no corporation or any foundation behind Friendica. Friendica was created by Mike Macgirvin who left the project to create Hubzilla which has a different focus than Friendica.
Friendica is a communication hub that can not only talk to other Friendica servers but also natively to servers that are using the Diaspora protocol (Diaspora and Hubzilla) and the OStatus protocol that is used by GNU Social.
Additionally you can use accounts of third party networks to read and post content with the use of Friendica.
Friendica currently supports bidirectionally (reading and posting) the following networks:
- GNU Social
- Mail (via IMAP and SMTP)
Also you can post content to these networks:
- Buffer (Facebook, Google+ Pages, LinkedIn, Twitter)
If you want to know more, have a look at the screenshots for a first impression or see the most important features and the requirements to install it on your system.