GNU social is a fork/continuation* of the StatusNet software (PHP, "OStatus" protocol). pump.io is a similar piece of software (node.js, "Activity Streams" pro

GNU social is a fork/continuation* of the StatusNet software (PHP, "OStatus" protocol). pump.io is a similar piece of software (node.js, "Activity Streams" protocol) written by the original StatusNet developers. *It started life as a fork, but in June 2013 they merged and it became the continuation.