Says Mundie (via Xbit):
I think there's an important distinction - and frankly one we did not jump on at Microsoft fast enough - between mobile and portable. Mobile is something that you want to use while you are moving, and portable is something that you move and then use. These are going to bump into one another a little bit and so today you can see tablets and pads and other things that are starting to live in the space in between. Personally I don't know whether that space will be a persistent one or not. [...] I don't know whether the big screen tablet pad category is going to remain with us or not.
Microsoft is expected to launch its Windows 8 tablet-optimized OS next year and some manufacturers are releasing Windows 7 tablets this year.