It uses digital certificates to validate the identities of all parties involved in a purchase and encrypts credit card information before sending it across the Internet. Not surprisingly then, merchants have been quick to develop and introduce a number of ways to limit their exposure to fraud. That's why a high proportion of fraudulent orders come from free e-mail addresses and as a result many merchants refuse to accept orders from them or at least perform additional checks. You can find a list of free e-mail domains on the AntiFraud Web site. For example, the Web site might display a US business address whilst the order requests delivery to be made to Eastern Europe.
Some merchants go even further and check out who owns the domain name.
This includes the customer's address and telephone number, the name of bank that issued the credit card, and the IP address of the computer from which the order was placed.