NPD's figures are estimates from people without access to real data.
Gruber says:
"It�s never been clear to me why reports like this are reported as fact. NPD doesn�t have some sort of magic access to Apple�s sales numbers, and Apple does not release monthly sales data. My understanding is that everyone who believes these numbers from NPD will be pleasantly surprised next month when Apple releases its actual sales figures for the current quarter."
And in MS's ad, the bimbo saying she is not cool enough has just reinforced Apple's own message (is it a coincidence that the same ad company produced the woeful Seinfield ads?)