Countless Ponzi schemes have been exposed over the years — involving real estate, oil, stock, old coins, you name it. Why do we keep falling for it?

Part of the seduction is the "pyramid of trust" in successful Ponzi schemes, says Robert Levine, professor of psychology at California State University at Fresno and author of "The Power of Persuasion: How We're Bought and Sold."

The pyramid of trust begins with the first satisfied customer, who spreads the word. Soon, it's not your trust in the perpetrator that lures you in — it's your trust in the friends of friends of friends of the perpetrator, Levine says.

An aura of exclusivity helps. Charles Ponzi accepted anybody's money, but because there was no advertising, you had to be in the know.

"Exclusivity is designed to make it seem like you're in a club that you're lucky to be invited to," says Barry Minkow, a convicted former scammer who now helps federal investigators unmask Ponzi schemes and other frauds.

"Ponzi and all of his successors tap into a fundamental part of human nature," says Mitchell Zuckoff, Ponzi's biographer. "One part of our brain tells us this is too good to be true. The other side tells us this is too good to miss. The key to any con is getting a mark to tip to the too-good-to-miss side.

"The combination of Ponzi's huge personality and the enormous if brief success of his scheme, combined with the tremendous publicity which surrounded it, is ultimately what attached his name to it."