Diaspora is a social network like Facebook or Twitter, but at the same time, it's very different from most other social networks. Rather than having all of the users on one single server, Diaspora has many users running their own social sites all over the web, and they can all talk to each other through Diaspora. We refer to this concept as decentralization.
What is Decentralized Social?
Decentralized social is the idea that you don't need to join a massive social network like Facebook, Twitter, or Google+ to keep in touch with your friends. The principle is simple: you're on one site while your friend is on another, but you can still follow each other online, post status updates, comment on public discussions, share pictures, like things, and send private messages to one another as if you're talking to each other on the same site.
Why is decentralized social important?
There are several fundamental problems with the way existing social networks work. Networks like Facebook are massive data silos with hundreds of millions of active users on a single site, and many networks of that scale sell your personal data to advertisers. Social networks out there today also have a habit of censoring what you can and can't say, which is problematic for anyone involved in political activism.
Who's building it?
Diaspora is a community effort built for the people, by the people. It is developed by dedicated community members in their spare time. This project is Free Software, meaning that anyone can download our code, look at all the different parts, change it for themselves, and best of all, they can contribute ideas and changes.