I thought this article from Jack Schofield was interesting. Are Netbooks an additional device? My Netbook is certainly additional, but would be my main device if I spent a lot of time wandering around the streets of London (or similar). But overall I think this:

Yes, I’m shamelessly taking inspiration from one of my favourite blogs: Indexed. And I may do more. (I apologise for using PowerPoint for the diagram, but I just don’t have a scanner to hand.)

By the by, do you know how successful Windows is on netbooks?