The sharedInstance site runs on Octopress and GitHub Pages. That means you can clone this repo, switch to this branch (git checkout source), make changes (anything from a single typo fix to whole paragraph rewrites are welcome!), and send a pull request.
The source in this repo that's unique to sharedInstance, as well as the sharedInstance articles, are licensed under Apache License 2.0. Octopress itself is licensed under the MIT License.