BananaFish - 2:29 am on Feb 17, 2009 (gmt 0)
The reason for the $1.00 authorization is for fraud check. The amount of $1.00 is authorized so that AVS and CVV2 can be checked without placing a large hold on the customer's account. The issuing bank does not check AVS or CVV2, they simply return this information and place a hold on the customers funds. If the transaction does not pass fraud checks, such as AVS (perhaps the customer mistakenly entered an old address), only $1 is held rather than the entire purchase amount.