Disclaimer: I’m not an addon developer, just a concerned end-user that tries to be involved with the Mozilla community and follow the development process. Hopefully this will still make sense.
Updated June 23: Added links to http://blog.mozilla.com/addons/2011/04/19/add-on-compatibility-rapid-releases/ – thanks @jruderman for pointing this out.
Firefox 5 shipped yesterday, on time, the first of many releases on the new, accelerated rapid release schedule.
There’s been a lot of talk of rapid release being a negative for users, particularly due to addon compatibility. While it’s certainly a valid concern, it’s not as bad of a situation as it appears on the surface. The Mozilla developers, in particular the Addons.mozilla.org team have been doing a lot to prepare for rapid release and to make the transition less painful for both users and addon developers. The addons team has even put an automatic compatibility update in place that finds addons that will work and marks them compatible early in the release cycle.