GitHub is a social coding website and source-code hosting service that uses Git as its version control system. Launched in 2008, GitHub already boasts nearly 1.7 million people hosting nearly 3 million repositories. Like most social networks, GitHub allows users to create and follow feeds associated with each other’s projects. It also extends the social paradigm to include network graphs that show repository usage. You can think about GitHub as a social network, a la Facebook, but just for software developers.