The idea that Android could be a top dog OS would have been laughable just a few years ago but as of 2013 it had the largest user base of any mobile operating system. Android tablets, which had long played second fiddle to the iPad, finally outsold Apple's signature tablet in that same year (note: now they're well in the lead). That was also the year that Google's OS hit 1 billion activations and Android's share of the global smartphone shipment market was a whopping 81.3%. Now according to a report from research firm Gartner, actual Android device shipments will top 1 billion in 2014. Not too shabby!
