FairUCE (which stands for "Fair use of Unsolicited Commercial Email") is a spam filter that stops spam by verifying sender identity instead of filtering content. It can stop the vast majority of spam without the use of a content filter and without requiring a probable spam or bulk folder that needs to be checked periodically. As one of the first spam filters that uses sender identity rather than email content to determine if it is legitimate, all this can be accomplished quickly using simple, inexpensive tests.

Content filters require frequent maintenance and require a great deal of processing for complex techniques such as bayesian, heuristics, fingerprinting, etc. The techniques spammers use to get past content filters become laughable, because it doesn't look at what they say, only at who they are. It virtually eliminates spoofed addresses, phishing, and even many viruses with a few cached DNS look-ups and a couple of if/else statements. Sender identity is the spam-fighting tool of the future. The author of this technology went from over 400 spams a day to just one or two.