[asveikau]

I recall that sourceforge gave you an SVN repo and an issue tracker, so it was kind of a hub for running your project. What made GitHub stand out was easy forking, and the pull request code review UI, and slick source history UI. A lot of this was aided by the technical innovation of using git and making git such a central piece.

[ashleighz]

Yup, this was it for me, GitHub was actually pleasant to use, to browse, PRs were easy, branching was easy, PRs with reviews/comments/etc were a brand new concept, especially as SourceForge and Google Code were hosted only on SVN which constantly fucked up/corrupted data in my experience

The closest thing to PRs that I knew was reviewboard, and that was a bolt on to SVN, not an actual proper integration