As I understand their global version, which I use, sources its data from the likes of metacrawler.com and dogpile.com which account for somewhere between 0-3% of global search traffic (if I remember rightly).
Anyway my point.... Does anyone have any idea where they might be sourcing their UK data from? It will be interesting to see how it turns out, I know I for one can't wait to get my grubby little mitts on it, errr I mean I'm looking forward to it!