GitHub can host various Git libraries and provide a web interface, but it is different from other libraries such as SourceForge or Google Code.
Different services, the unique selling point of GitHub lies in the simplicity of branching from another project. Contributing code to the project is very simple: first click the "fork" button on the project site.
Button, then check out the code and add the changes to the just separated code base, and finally apply to the project leader for code merger through the built-in "pull request" mechanism.
Git is a distributed version control system, which was originally written by Linus Torvalds to manage Linux kernel code. After its launch, Git has also achieved great success in other projects, especially in the Ruby community. At present, many well-known projects, including Rubinius and Merb, are using Git. Git can also be used by deployment tools, such as Capistrano and Deployer Vlad.