Daala is the codename for a new video compression technology. The effort is a collaboration between the Mozilla Foundation, the Xiph.Org Foundation and any other contributors that wish to help. The goal of the project is to provide a video format that's free to implement, use and distribute, and a reference implementation with technical performance superior to H.265. For more information, see the Daala wiki.
To get a sense of how well Daala performs in comparison to other codecs, check out Are We Compressed Yet?
The wiki has quickstart pages for Linux/OS X, Windows, and Windows MinGW64.
Daala uses the GitHub Issue Tracker and the Rietveld code review tool. Jenkins is used for continuous integration.
There's an IRC channel #daala on chat.freenode.org. If you don't have IRC set up you can easily connect from your web browser.
You can also subscribe to the daala mailing list.