[phee]

IIRC git was already a huge success, i.e. most big freesoftware projects (Linux, GNOME, xorg, gstreamer and many more) ditched other VCS for it, when github was still in its early stages.

[pjmlp]

I remember quite a few (Go, SDL, Java,Google Code repositories...) using Mercurial until switching to git due to peer pressure was unavoidable.