GitHub is a Web-based revision control hosting service for software development and code sharing.
GitHub offers free public repositories and collaborations for open-source software creation and charges small and large businesses for private repositories and collaboration. From a social perspective, GitHub allows users to change, adapt and improve software — each project is called a "fork" — in its public repositories. Users can work together in teams or alone. Public users create profiles which display repositories and public activity and help programmers find projects.
GitHub was started in 2008 and based on Git, an open-source code management system built created by Linus Torvalds to make software builds faster. After a security breach on the standard Linux kernel distribution site at kernel.org in 2011, Torvalds released the 3.0 Linux kernel on GitHub. Other groups with GitHub public repositories include Red Hat's JBoss software, Twitter, Microsoft Windows Azure, the Open Compute project and Mozilla.