IMHO: Because Github just came at the right time for a free "no strings attached" project hosting solution when Sourceforge decided to become evil. That was the reason why I switched to Github anyway.
That Github used this strange version control system cobbled together by the Linux kernel devs for their specific workflow was a bit weird, but that wasn't a showstopper for moving to Github.
After all it was just one amongst many version control systems, and a VCS shouldn't be the centre of the universe anyway, over time Github would probably offer different systems anyway after they become more popular.
Nobody expected that Github was essentially a Trojan horse ;)
It’s even more specific than that. GitHub chose “free public repos, paid private repos” as their business model and git as their DVC. Bitbucket chose the opposite.
GitHubs model is incredibly more viral and thus git won (sadly IMO).
That Github used this strange version control system cobbled together by the Linux kernel devs for their specific workflow was a bit weird, but that wasn't a showstopper for moving to Github.
After all it was just one amongst many version control systems, and a VCS shouldn't be the centre of the universe anyway, over time Github would probably offer different systems anyway after they become more popular.
Nobody expected that Github was essentially a Trojan horse ;)