Google recently opened up a preview of our new Caffeine update, and I wanted to give a little more background on this change. At the Real-Time CrunchUp a few weeks ago, I joked that the half-life of code at Google is about six months. That means that you can write some code and when you circle back around in six months, about half of that code has been replaced with better abstractions or cleaner infrastructure. Six months is an exaggeration, but Google is quite serious about scrutinizing our codebase regularly and rewriting the parts that don’t scale well to make them more robust, more elegant, or faster.