The latest smartphone usage figures from the US show that there are now more iPhones in use than all Windows Mobile-based handsets put together.
So claims data from market research firm comScore, which publishes monthly reports on the number of devices in active use on the various mobile platforms.
And while October's figures show RIM's BlackBerry OS still leading the pack with nearly 15 million active users, Apple has moved into a clear second place with just on nine million, with Windows Mobile now trailing with a shade over seven million.
The monthly figures also show corresponding figures from three, five and eight months ago, and while every OS has gained users since February, Windows Mobile's numbers have grown the least of all the competing platforms, and at less than 10 per cent of the pace of Apple's OS.
The news adds to what has already been a bad week for Microsoft's mobile division, with head of the UK operation Phil Moore letting slip on Tuesday that Windows Mobile 7 would only hit the market towards the end of 2010.
By that time its market share is likely to have eroded still further in the face of the iPhone's continued success and the barrage of new Android phones expected in the first half of next year.
At this point Android remains a peripheral presence in the US market. October's figures show only just over a million handsets were running Google's much-hyped mobile OS, leaving Android trailing not only RIM, Windows Mobile and Apple, but Palm and Symbian too.
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