Continuous Deployment at IMVU: Doing the impossible fifty times a day.
From what I have read Facebook use a similar method: commit and deploy often and rollback if something messes up. We also use this method on Plurk.com and have done so for about a year. Thought, IMVU's case is pretty extreme :)The major problem is rolling back client side changes (that are located in scripts or CSS). This is pretty costly to rollback, because of browser cache - we solve this by having real versioning of the static files so we can force a refresh of browser cache (real versioning = script_{timestamp}.js and not script.js?v={timestamp}).