Ryan Paul writing for Ars Technica:
When making a purchase, online shoppers are confronted with a validation check that requires them to supply a password — in addition to the standard security code that is on the card itself — in order to prove that they are the real owner of a credit card. … Some of the credit card companies take advantage of [this system] by wrapping their implementations of the validation system in draconian terms of service that force users to agree to accept full liability for credit card fraud.