Answer:
a fraud is a scam, or someone who scams people, a fake offer our business transaction. and it persists because people are stupid gullible trusting creatures that cannot use common sense to figure out that something is too good to be true. example:
"THIS IS NOT A SCAM YOU ARE THE 100,000TH PERSON TO HAVE VISITED THIS SITE, CLICK HERE FOR $10,000" that is a fraudulent add.