Apple announced that they sold two million copies of Leopard in the first two days. Blackfriars’ Marketing describes it this way:

I tried to find similar statistics for the Microsoft Vista launch, but the best I could come up with was that Vista sold 20 million copies in the first month (February), resulting in an average sales rate of 714,000 a day. Both numbers reflect pre-orders and machine installs, not just upgrades. So at least for now, Leopard is running neck and neck with the Windows Vista install rate.

I beg to differ: Leopard is not running neck and neck with Vista. Windows has ten times the market share, at least ten times the number of computers to service. Which means that if Leopard is selling the same number of copies, then Leopard is outselling Vista ten to one. Unlike Vista, Leopard is getting excellent reviews, and you can bet that no one is going to an Apple dealer and asking for Tiger instead of Leopard on their brand-new Mac. Nor does Apple have to skew the numbers to make it look like it’s doing better than the last OS release; Tiger took a month to sell 2 million copies. True, Apple has sold a lot more Macs since then, but not that many.

Oh yes, and let’s not forget that Leopard pre-orders only began a week before release, while Vista’s began months early–and included all Windows PC sales of XP in that 3-month period because they included coupons for Vista.