Well, you didn’t see this coming, did you? Hotmail, which due to some feat of magic remains the world’s most popular webmail client, has exploded on Apple’s mobile products since the introduction of the latest firmware edition, iOS 5.

According to Microsoft, some 2 million Hotmail accounts have been linked to an iOS device since the 5th version was released, and some 100,000 are doing so daily. Changes in iOS 5 made it much simpler to link a Hotmail account to an iOS gadget, and the response has been large thus far.

According to Microsoft, Hotmail has around 360 million unique monthly users, so the overlap between the iOS gadget owners and Hotmail users must be quite wide. But there is something vaugley dirty, you must feel, about Hotmail on an iPad. It’s a bit like bringing a 1999 Honda Accord to an open track day. It’s a bit out of place.

Of course, Hotmail has been making strides to capitalize on its massive userbase, and to combat the rise of Gmail, which will eat its proverbial midday meal if it doesn’t radically reform. It appears to be trying to do just that, if its most recent product news is any indicator.

About their forthcoming redesign, this is what we said: “Today’s update is cosmetic, and functional. The crucial new feature released is ‘Categories,’ which is the equivalent of Gmail’s ‘Label’ feature. That Hotmail lacked this for so long shows exactly how far Microsoft has fallen behind Google in this space. Still, the direct feature rip is welcome, as Labels are an important element of Gmail, and were much needed in Hotmail.” Progress is progress, but with Gmail improving itself, if Hotmail can catch up is a question that feels answered

Microsoft says that it is just “getting started” on iOS. We’ll see.

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