Another Way of Slicing the Android, iOS, RIM Horserace: Facebook Monthly Actives

For mobile developers, there are more than plenty of statistics abound to gauge relative market size for different smartphone platforms.

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.

By this metric, Android is growing five times as fast as iOS, adding just over 99,000 monthly actives a day for Facebook’s native app. Facebook for iPhone boasts 63,021,033 monthly actives to Android’s 25,300,775, but it only adds about 19,750 monthly actives per day. When you add in HTC, Samsung, SonyEricsson, LG and Droid phones — many of which run Android — iOS still has a three-to-two lead for now. One other important detail to note is that Facebook for iPhone’s growth may also be on hiatus this week as consumers wait for the phone to come to Verizon on Feb. 10.

Other platforms are interesting to watch as well. Although Windows Phone 7 came to market last fall after a two to three year delay, it has shown a steady growth rate. Facebook for Windows Phone 7 has 320,807 monthly actives with the highest growth rate of any platform over the past week at 5.9 percent.

Snaptu, a company that helps Facebook reach feature phones that it doesn’t design native applications for, also boasted 3 percent growth this week by adding 119, 586 monthly actives to reach 3,565,651. Two weeks ago, Snaptu announced a partnership with Facebook to overhaul its apps for more than 2,500 models of feature phones.

Facebook Usage on Feature and Smartphones

1. Facebook for Android25,300,775+693,653+3%
2. Facebook for Blackberry Smartphones29,281,263+249,866+0.8%
3. Facebook for iPhone63,021,033+138,280+0.2%
4. Snaptu3,565,651+119,586+3%
5. HTC Sense5,946,870+95,833+2%
6. Ovi by Nokia2,468,604+74,879+3%
7. Samsung Mobile5,106,133+54,388+1%
8. DROID1,910,688+42,536+2%
9. LG Phone963,382+25,787+3%
10. Facebook for Windows Phone320,807+17,951+5.9%