The code is available at an official Trac page and is licensed under the Common Public Attribution License, which means that anyone running the code must publish changes publicly, but that the software is free for commercial use. Some of Reddit's code is not being made public, mostly stuff that deals with anti-spam and anti-cheating algorithms, according to Reddit.

"Since reddit's beginning, we have stood on the shoulders of giants in the open source world. Every library, tool and platform we depend on is open," said the announcement blog post. "Until now, the only portion of reddit that wasn't freely available is reddit itself. We are proud and excited that we're finally giving back to the community that has given us so much."

It makes sense for Reddit, which has grown because of very passionate and technically savvy community, might go this route. Open sourcing Reddit's code will very likely lead to a stronger product and tighter community, and not to the birth of strong competitors. Anyone who wants to create niche Reddits on topics that the site doesn't adequately cover is now free to do so, however.

Reddit is written in Python. An explanatory video from the company is below.