To everyone complaining about the name: it is just the name of the advocacy/development group. You don't call SMTP mail 'IETF mail', nor should you call call whatever they come up "dark mail alliance mail".
To Euro-English speakers, 'git' is a rather coarse pejorative term for a person:
http://www.etymonline.com/index.php?term=git
It's fairly vulgar, of a similar coarseness to calling someone a 'stupid fucker' in US terms.
The in-joke being that Mr Torvalds chose the name specifically to cause offense.