Why Github actually won

In the end we won because the open source community started to converge on distributed version control and we were the only ones in the hosting space that truly cared about how developers worked at all. The only ones who questioned it, approached it from first principles, tried to make it better holistically rather than just throwing more features onto something existing in order to sell it.

Full story here. A great run-down by Scott Cahon himself on why Git and then GitHub won the version control system war.