Microsoft hasn't exactly been dishing out hard sales numbers since launching Windows Phone 7 at the tail end of last year, preferring to focus on the numbers of licences it has sold to manufacturers (mainly because it's a higher number).
But thanks to a little fuzzy maths involving the all-consuming colossus that is Facebook, WMPowerUser reckons the number of Windows Phone 7 handsets actually out in the wild numbers between 3.7 and 3.9 million.
We'll not replicate the WinPho blog's actual sums here – head over to the original post for the full breakdown – but it arrives at its figures by comparing the sales data we received recently from Gartner with Facebook activity data.
By seeing how many new Facebook users were added in the quarter and checking that against the number of phones Gartner says were sold, the site arrived at a phones per Facebook user ratio, which can then be applied to the wider Facebook user tally.
The interesting point it raises, however, is that if the figures are accurate, Windows Phone 7 sales are actually slowing down, not speeding up as the non-stop evangelical voice of Steve Ballmer would have you believe.
Could that be something to do with the painful lack of anything resembling new hardware anywhere on the horizon. We know Nokia's Windows Phones are coming, but seriously – it would be nice if someone could dish up the odd handset between now and then, chaps, and not just rumours...