We’ve always strived to be as open and transparent with our users as possible, and this is the next logical step. When we say ‘open-source’ we mean specifically that the code behind reddit is available to the public for download, and we’re inviting the public to submit code to help improve the site.
The code base is available at code.reddit.com and licensed under Common Public Attribution License meaning if you made any changes to the code base you have to submit those to the community and you should always mention your code is based on reddit. Code related to anti-cheating and spam protection is not available.
It feels good when some of the popular sites turn their code to open source way. The code is based on Python if you care.