Dobly spam reduction
An article on Wired details 2 open-source spam filters that claim to be more effective than many costly commercial spam filters. One of the products is Dspam, which includes a technique that the software author has dubbed "Dobly" in homage to the Dolby noise reduction system. Dobly cleans some of the "noise" that spammers put into their e-mails to fool spam filtering systems. Essentially, Dspam uses Dobly to suppress noise before the e-mail is run through other filters.