VIA marketing manager Richard Brown picked up that statistic at a conference hosted by Phoenix, the folks who develop the BIOS software used on millions of comptuers. One possible reason why netbook sales are so much higher in Europe than the rest of the world is because European cellphone carriers offer a number of low cost 3G wireless data plans for laptop users. Ultraportable computers are a lot more attractive if you can use them to connect to the internet wherever you are. And several wireless providers even subsidize the price of the hardware when you sign up for a long term service plan.
If US carriers start to offer similar packages, or make it easier to tether popular smartphones like the iPhone and T-Mobile G1, perhaps it will help grow the market for netbooks in the US. Then again, as Chippy at UMPC Portal points out, Europe has about twice the population of the US.