Attempts to figure out exactly how many Windows Phone 7 devices have been sold continue, with Microsoft still reluctant to give out the official stats. The latest batch of numbers comes courtesy of the Windows Phone 7 Facebook app, which currently lists over 135,000 monthly active users, and WMPowerUser's tracking over the past few months.
They're assuming that most Windows Phone 7 owners will have logged into the native Facebook app, and that the current total the social networking site lists is likely to be roughly the same as the handsets in the wild. Actual downloads of the Facebook app in the Windows Phone Marketplace, meanwhile, reached just over 80,000 by the weekend, enough to make it the second most popular title in the download store.
There are plenty of assumptions and disclaimers along the way to these figures - it assumes everyone with a WP7 device also uses Facebook, for a start - but until Microsoft come clean with the true statistics we're likely to see more amateur calculations and anecdotal results. Yesterday an online deal search engine prompted controversy by suggesting Android devices were outselling Windows Phone 7 handsets 15:1.