this FFB concept seems ike a great tool to cut down on spam. in essence, the idea is to crawl any site listed in the body of a spam message (as determined by a black list; that's the weakest link) with a spider that serves no purpose: "If widely used, auto-retrieving spam filters [aka FFBs] would make the email system rebound.The huge volume of the spam, which has so far worked in the spammer's favor, would now work against him, like a branch snapping back in his face. Auto-retrieving spam filters would drive the spammer's costs up, and his sales down: his bandwidth usage would go through the roof, and his servers would grind to a halt under the load, which would make them unavailable to the people who would have responded to the spam. Pump out a million emails an hour, get a million hits an hour on your servers."