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.
Maybe it's more along the line of loss prevention positions at a retail store, which monitor customers' behavior in-store, and follow the ones that look suspicious. Applied to web activity, it seems like it might yield interesting results...