Promoters of penny stocks typically pitch these high-risk investments as if they were valuable real estate, like oceanfront property. With little money down, you can make a quick-and-easy profit. But in reality, penny stocks are more like swampland. And now, thanks to spam, the muck is spreading at an alarming rate, and efforts to stop it have so far been as effective as ordering the tide not to come in.

You probably trashed an e-mail message last December touting Goldmark Industries. A spam campaign predicted that investors would earn spectacular returns. One e-mail, which forecast the stock would gain 1,077%, said, "Watch GDKI [Goldmark's symbol] soar on Wednesday, Dec. 20!"