Verno wrote on Sep 17, 2012, 11:45:
Valve has usually said that the Steam list is ordered by raw revenue, I assume its just whatever is passing through the payment processor.
That makes sense- I think the live bestseller list on Steam is using a rolling last 24 hours or less time frame as opposed to this weekly summary.
XCOM is already chewing into pre-order bonus #3- complementary Civ 5. It's not even release week yet so I'm hopeful.