Intents is probably one of my single favorite under the hood features of Android as a user. Installing an app and having it instantly be able to exchange data with any other app on the system in a smart way makes the process so simple you don't really even have to think about it. It's one of the parts of Android I'd have a hard time living without.
In fairness, I do agree with Gruber that back button behavior on Android can be painfully inconsistent. That said, I also agree with you that it provides fairly important functionality on Android. I do wish developers would use it more consistently.
