How GitHub Conquered Google, Microsoft, and Everyone Else
I think one of the underappreciated point of github is its excellent business model. The freemium model of providing everything for free if your code is public and charging only for private repositories allowed them to grow exponentially with rising popularity among open source projects.<p>Sourceforge and Google code tried to cater only for open source projects, while never thinking that code hosting is the problem that needs to be solved.