Why should Apple pander to mindless curiosity?
As a public corporation Apple has an obligation to periodically report it sales in various categories. But beyond this, it has little interest in giving its competitors ANY information whatsoever as to how well its various products are doing.
If Apple announced - tomorrow - that it had sold 3 million iPads in the first week and a half of its introduction, all that would do is encourage more crappy "me too" products from the Samsungs, Acers, and Adam Inks of the world. And if, for whatever reason, it only sold 2 million during the "Black Friday" sales period, it would simply encourage iditiotic posts about how "iPad is losing its momentum.."
I have little doubt that by now Apple has well over a million iPad 2 units moved "into the channel" - and by that I mean in actual consumer's hands.
But beyond that, it is worth noting that this is a business. Its not a baseball game, where every development is recorded on some sort of scoreboard.