Github is rolling out a new wiki system which uses a git backend to store data. This is an awesome feature, and one that I've wanted Github to add ever since I started using a similar feature at Google Code. It's great to be able to download all the wiki pages as a repository and work with it locally using my normal editing tools.
Whiteknight's rule of the internet #47: Raw TextArea controls in a browser are rarely good enough for anything, and should be avoided for any task besides extremely rare edits of small bits of text.
Only one of my projects on Github makes use of the wiki feature there: EmbedVideo. Last night I converted the existing wiki pages to the new git-based wiki system, and pulled down the repository. In a wild fit of productivity, I updated much of the documentation and filled in some of the blanks that I had left for too long. It's still not perfect (software documentation rarely is), but it's better than it was and it's probably good enough to get most users moving with some of the new features.
I love when tools get better, and compared to what they used to be the new Github wikis are certainly much much better.