PCWorld: Researchers at the University of California, San Diego (UCSD) said they've discovered a critical weakness in the spam ecosystem that could be used to help cut off the promise of economic returns fuelling the huge growth in spam levels:

In a paper delivered at the USENIX Security 2007 conference in Boston, the UCSD researchers said that while spammers use vastly powerful, distributed delivery networks to pump out junk e-mail, it's quite another story for the internet scams that form the real heart of the spam mechanism.

Such scams, for instance selling pharmaceutical products over a website, are typically hosted on a single website, the researchers found. What's more, a single site might host several scams and might also act as a spam relay.