Microsoft was known in the past for its attempt to "lock in" users to their products with proprietary file formats and other tricks, that make it difficult for users to go elsewhere. But for the most part, they have changed their tune in recent years, for example changing to XML-based versions of Microsoft Office documents which are easily reabable by OpenOffice.Org and other competitors.
But now, there is news that apparently Windows Phones - lacking internal Flash storage like the iPhone - is permanently modifying any MicroSD cards used in them so that they can never be formatted or reused by any other device.
Samsung have documented the feature for the Focus, saying that inserting a MicroSD card into a Windows Phone can be considered a “permanent modification” adding ”it will no longer be readable or writable on any other devices such as computers, cameras, printers, and so on”.So, if you are considering a Windows Phone, please be aware any SD card purchases should be considered a one-time expense that can't be recouped by reuse. It's a very strange way for Microsoft to have gone.
Microsoft too has warned of the permanent change, though it’s not entirely clear exactly what the OS is doing to the card.