Google’s Android chief Andy Rubin said last month that the OS is seeing more than 300,000 activations a day while Apple said in its most recent earnings call that the company has cumulatively sold 160 million iOS devices. Nielsen said today that Android, iOS and RIM are in a three-way tie among smartphone owners in the U.S.
However, a more relevant number to gauge potential market size for mobile app developers may be the number of Facebook users worldwide on each platform. Facebook is likely a decent proxy for smartphone users willing to download and engage with applications (outside of markets like Japan, China and South Korea where the company has a weak presence). Unlike the statistics that Apple has released, it also takes out users who may have more than one iOS device.