The co-liquidator of the biggest feeder fund for Bernard L. Madoff Investment Securities says some investors in the Fairfield Sentry funds had knowledge of the massive financial fraud and profited as a result.

FORBES: EXCLUSIVE: Some Fairfield Investors Knew About Madoff Ponzi and Profited

But this massive fraud is at the heart of the financial meltdown and the entire world was hurt.

FORBES: DeMarco "Completely Puzzled" Over Derivatives Flap

PayPal and Amazon have developed fraud detection tools that depend on massive datasets containing not only financial details for transactions, but IP addresses, browser information, and other technical data that will help these companies refine models to predict, identify, and prevent fraudulent activity.

FORBES: Anti-Fraud Is Big Opportunity For Google, PayPal, Amazon