Electron Gun's Geologist talks about pre-orders and rationality in the virtual marketplace:
"A basic tenet of economics is that a market transaction should make both parties better off than they were before the transaction took place. Buying a copy of the latest blockbuster title gives the store more money and the customer hours of entertainment. Presumably, if the game is not worth the money spent, the customer will not buy it. Otherwise, s/he is said to be acting irrationally. This brings up an interesting question about how pre-ordering games affects consumers’ normally rational behavior."