Progress on accessible-app.com
Caution! This article was published over a year ago, and hasn't been updated since. Situation, software and support of the topic below could have changed in the meantime.
Just a quick heads-up: Accessible App (finally) received a content update, and it's a new pattern called "Showing progress". It deals with communicating interstitial (or: loading) states of web apps to screen readers by using the <progressbar> element in combination with focus management. I came across this strategy while working on the new ownCloud Web UI, and thought it is worth sharing.
As for any other content on the site, please contact me (or contribute to the project itself on GitHub) if you find any flaws or see room for improvement.