Here's a number that might surprise you: 75% of all smartphones use the Android—not Apple's iOS—operating system. And though your customers might still use iPhones and iPads in greater numbers, you can't ignore the astonishing gains in the mobile market by Google's Android OS. (This presentation from Mutual Mobile demonstrates just how far Android has come.)

Android's checkered past is fading away

There's a reason for Android's delayed success: Earlier versions simply weren't up to iOS snuff.  Now in its third generation, however, Android has hit its stride with an improved user experience, polished apps, and appealing devices.

Android is Facebook users' OS of choice

Of particular note to international businesses: On a worldwide basis, more Facebook users now use Android smartphones: 189.7 million vs. 178.3 million.

Android is the fastest-growing mobile OS

Android continues to chip away at Apple's shrinking global market share. And though this dominance is less profound in the United States, it still leads iOS in smartphone users: 51.9% vs. 34.3%.

Android now threatens Apple's tablet dominance

Tablet ownership among US adults doubled between 2011 and 2012. In that same period, Android's share of the tablet market more than tripled—from 15% to 48%. What will 2013 bring?