(I don't like advertising on these threads, but since somebody asked me directly I'll reply.)
Credit card companies protect consumers, but not merchants. When you call up your bank to report that a transaction was fraudulent, the credit card company reverses the transaction and withdraws the money from the merchant's account. That reversal, called a chargeback, can occur months after the original sale. Merchants can lose thousands, even millions, of dollars per month due to chargebacks.
That means anybody who sells stuff online needs a way to detect fraud on their site in real time, and that's what Sift Science does.
If you run a web site with a payment form, give it a shot: http://siftscience.com.