GitHub is a web-based Git repository hosting service, which offers all of the distributed revision control and source code management (SCM) functionality of Git as well as adding its own features.
What is Git? Git is an open source program for tracking changes in text files. It was written by the author of the Linux operating system, and is the core technology that GitHub, the social and user interface, is built on top of.
Unlike Git, which is strictly a command-line tool, GitHub provides a web-based graphical interface and desktop as well as mobile integration. It also provides access control and several collaboration features such as wikis, task management, and bug tracking and feature requests for every project.
GitHub offers both paid plans for private repositories and free accounts, which are usually used to host open-source software projects. As of 2014, GitHub reports having over 3.4 million users and with 16.7 million repositories making it the largest code host in the world.