Git is a Distributed Version Control System (DVCS), authored by Linux Torvalds and designed for Linux kernel development.
The big advantage of Git is it's advanced revision tracking system, keeping tabs on each change. This provides the ability to revert entire directories to past snapshots and revert edits or mistakes. Since it's distributed, where all nodes are equal, anyone can pull from a repository, fork, and push changes back. Even if the server goes down, the users could simply make their node public.
Because of the specific qualities of the DVCS, it has uses beyond software versioning. A plan to make the repository truly independent from a central server has been explored with Gittorrent, and if implemented, could possibly have a huge social effect on the internet.
needs more info
sudo apt-get install git