[degroat]

Github's numbers are going to be biased towards programmers who use languages that are more progressive. .NET developers aren't using Github and neither are many older companies that are still using self-hosted SVN and CVS repos.

[earlz]

".NET developers aren't using Github" says who? I find about 80% of open source projects for .Net on Github. With the other 20% being split between codeplex, sourceforge, Google Code, and self-hosting/publishing

[pjmlp]

Open source is the keyword.

Most corporations would faint just with the idea of hosting their code outside premises.

[addflip]

Yep. My company is using a throw back gem(Visual Source Safe) to host our VB6 apps written in '98.