GitHub is a web-based hosting service for software development projects that use the Git revision control system. GitHub offers both commercial plans and free accounts for open source projects. According to the Git User's Survey in 2009, GitHub is the most popular Git hosting site.

The site provides social networking functionality such as feeds, followers and the network graph to display how developers work on their versions of a repository. GitHub also operates a pastebin-style site called Gist, wikis for individual repositories, and web pages that can be edited through a git repository. As of January 2010, GitHub is operated under the name GitHub, Inc.

The software that runs GitHub was written using Ruby on Rails and Erlang by GitHub, Inc. (previously known as Logical Awesome) developers Chris Wanstrath, PJ Hyett, and Tom Preston-Werner.

Manage Teams with Organizations

Whether you're running an open source project or a Fortune 500 company, Organizations simplify team management. With teams you can give your developers as much or as little power as they need, from the ability to create projects on behalf of your organization to read-only access on existing projects.

Team permissions: Read-only, read-write, and admin-level access.

Best of all: create as many teams with as many members as you need. There are no limits on teams or their members.

Shared Administration

Organizations allow the people who oversee your group's billing information and the people who oversee team management to work together brilliantly using their existing, free GitHub accounts.

Gollum Wikis

Our wikis are powered by gollum — an open source wiki engine created by GitHub. They’re backed by Git, clonable, usable offline, and accept a plethora of text formats — what’s not to love?

Supported formats: Markdown, Textile, RDoc, Org Mode, Creole, ReStructured Text (ReST), ASCIIDoc, POD and Roff.
And of course since gollum is open source if there’s a text format you’d like to use that we don’t support you can contribute a parser!

Git Backed

Since every wiki is a git repository, your wikis are importable and exportable by default. Just clone your wiki locally and push it up at another time — all your content, images, and history stays intact.
git clone git://github.com/defunkt/resque.wiki.git

Next Generation Issue Tracking

Every GitHub repository comes fully loaded with a next generation issue tracker so you can stay on top of bugs and focus on features.

Assignment, labels, and milestones help manage large projects while Gmail-style keyboard shortcuts make Issues perfect for a simple TODO list or an open source project's bug tracker.

Only teammates and collaborators can create and view issues on private repositories. Anyone may create and view issues on public repositories.
Pull Request integration and the ability to close or reference issues from commits help bring your workflow closer to your code.

Futuristic Code Review

The year 3000 called: they want their code review back. But we're not giving in. Pull Requests are living discussions that streamline the process of discussing, reviewing, and managing changes to code.

GitHub Pull Request = Code + Issue + Code Comments

Each Pull Request takes into account not only what you would like pulled but also where you intend those changes to be applied. From there your team can discuss the changes as a whole, individual parts, or even specific lines. Later commits addressing concerns or ideas appear as part of the discussion.

Our pull requests are everything you've ever wanted in code review and more. If you're unsure, just check out open pull requests for some of ourpopular open source projects to see them in action