I’ve been using app tabs in Firefox for a few weeks now and really like them. The first thing I did though was to slim down the page that is pinned. So instead of seeing this:
Because that is the “app” that I want for Google Reader… not the entire page.
This is done with a Firefox JetPack add-on that I cooked up (to play with the new add-on/jetpack system), but can probably just as easily be done with a GreaseMonkey script.