In addition, plenty of iOS's features have been updated and refined, and user interface conventions have been tweaked across the entire OS. Apple's also put an emphasis on rolling out certain features to both its mobile and desktop operating systems--Facebook integration, Mail VIPs, etc.--ushering in a new era of giving the two platforms parity when it makes sense to do so.

Five years after its debut, iOS 5 was already a mature operating system, a stable foundation upon which to build. With all that Apple had already added to it, you might have wondered what was next for the mobile operating system. As it turns out, there's plenty.

Every iOS release has its marquee feature, and with iOS 6 it's unquestionably Maps. The app has gotten a in-depth makeover, perhaps the most thorough ever to be applied to one of iOS's built-in applications.

The bow-to-stern overhaul starts deep under the hood, where Apple has replaced the mapping engine that in every previous version of iOS was provided by Google. In its place, Apple has rolled its own solution, supported by mapping data from GPS maker Tom Tom, OpenStreetMap, and a cast of thousands.