IBM has announced a new anti-spam initiative called FairUCE that will not only block SPAM, but will redirect the SPAM back at the senders. The software uses a giant database of known SPAM senders, which is similar to the Blackhole and Whitelists that many businesses use to block SPAM. IBM then uses this technology to direct SPAM back at the senders; however there is a problem in making sure that the redirection is hitting the right systems. Often the SPAM companies compromise innocent systems and use the zombie computers to send the SPAM, as many SPAMs are in fact sent from botnets and things similar to that.
IBM says that they are not concerned about liability, even in cases where innocent senders might be misidentified as spammers, because all the technology does is bounce back the e-mails.