It would appear that The Motley Fool has made a fool of Gadgetorama (and a few other sites) with their T-Mobile G1 pre-order estimates. It would appear that The Motley Fool used some tortured math to get those estimates. Essentially, it appears that the basis for the calculations was an estimate that HTC would sell up to 500,000 units in the fourth quarter. The problem: This number is for the entire quarter rather the pre-order.
As the article points out, if T-Mobile really had 1.5 million pre-orders on hand, would they and HTC not be announcing this everywhere they could? Such numbers would also eclipse the Apple iPhone 3G debut (1 million sold over first weekend) which took place in 20 countries and was accompanied by significantly more hype.
We will only know exactly how successful the pre-order was for T-Mobile if and when the company decides to share those numbers with us.