"Github makes it substantially easier to share and collaborate."
Unless you're using git, in which case, it's exactly the same: unlike facebook, I don't need my best friends to be in my git repo to make it useful.
In any case, I'm sure there are some folks for whom pull requests or browser-based editing (again: not unique to github) make the difference. But for a team of developers who need private repositories, it's six of one, half a dozen of the other.
Unless you're using git, in which case, it's exactly the same: unlike facebook, I don't need my best friends to be in my git repo to make it useful.
In any case, I'm sure there are some folks for whom pull requests or browser-based editing (again: not unique to github) make the difference. But for a team of developers who need private repositories, it's six of one, half a dozen of the other.