If you want to make use of the webapp mode on ios you have to make sure you don’t follow normal links otherwise safari will open. Of course there are more reasons to make an application singlepage but this was our main motivation.
We were building a webapp that has to work on older browsers without JavaScript. Naturally we're trying to reduce duplications so we didn't roll with JS Models but delivered finished markup over XHR. This worked really good as long as the frontend was "stoopid" and just displaying things but became a bit of a hassle when we started to add functionallity.
We already hosted a well received and interesting YUI3 introduction training. You can read about it here.
We initiated a new open source project called Jackalope. Its purpose is to bring JCR via Jackrabbit to the PHP world. The Team working on it currently consists of Christian Stocker, David Buchmann, Tobias Ebnöther and of course we would welcome you too! :) We use the Apache License and are very open minded about collaborations, inputs and wishes.