Its seems that Windows are attempting to upgrade everyone to a single Windows OS. How are they doing this? Well they're making the update completely free.
If people (or more importantly companies) take advantage of this, it'll mean that the vast majority of Windows users will be using the latest IE and the older generations of the browser should fizzle out of existence. This is great news for developers.
There is a lot more perks to having just one major OS to deal with. This is why Apple products are so adamant that its users upgrade whenever possible. For some reason unlike Windows users, Apple users are more than happy to do so.
Hopefully with the gift of free software this mentality will change.
It's amazing that Windows 7 users and Windows 8 users will all be able to upgrade and come forward to a single version of Windows. As a developer (both web and apps) it'll be nice to have people on an "evergreen" Windows where I can do things like Feature Detection and not think as much about versioning.