http://www.bbc.co.uk/programmes/b006m9ry (10:35)
Not sure if people outside of the UK can watch that so here's another article about it.
http://www.pcworld.com/article/239631/unique_kt_spider_phone_transforms_into_a_tablet_laptop_or_handheld_gaming_device.html
Basically the tl:dr is that it's a smartphone that slots into a tablet which can then become the screen of a notebook.
Imagine being able to buy a bundle of hardware (phone+tablet+notebook) which costs under $1000, has permanent net access courtesy of the phones 3g and which you can really use for work (notebook), play (tablet) and communication (phone) and does all of these things well.
It seems to me this could very quickly make Microsoft a major player in the smartphone & tablet space while retaining its existing desktop dominance.