One of the quieter improvements in Apple's iOS 5 for iPhone, iPad and iPod touch (see my review) is explicit support for Hotmail accounts via the Accounts settings panel. This means that Hotmail users can now easily integrate their email, contacts, and calendar with their iPhone and other Apple devices without having to jump through hoops as before. And the change has seen a dramatic increase in Hotmail usage on iOS: According to Microsoft, over 2 million users have configured Hotmail accounts in iOS 5 already.

"Hotmail is the world's leading email service, and last year we added support for Exchange Active Sync, allowing customers around the world to sync their Hotmail inbox, calendar, and contacts to their mobile phones through the power of Exchange," Microsoft's Chris Jones writes. "Although we've had this support for a year already, with the release of iOS 5 it is now even easier to set up Hotmail on your iPhone or iPad."

How much easier? Now, all you have to do is choose Hotmail from the list of account types, enter your email address and password, and choose which services to sync. Previously, you needed to go through a more complex Exchange-style configuration that required you knowing some server information.

In addition to the 2 million who have already configured Hotmail accounts on iOS 5, Microsoft says that another 100,000 new iOS 5 devices are being set up with Hotmail every day. Most of these devices are iPhones, with 64 percent being iPhone 4 or 4S handsets.

Microsoft notes that it now offers a dedicated Hotmail client app on Android as well.