While a person can easily recognize spam, it is not easy for computers because they do not "understand" language. Spammers have also learned to defeat most content filters based on phrases and keywords. While you may see "free money" on the screen, the email message may not even contain that phrase; instead, complex HTML code visually places those two words next to each other. Without a vision system, a computer cannot recognize this obvious phrase.

The best attempts to block spam according to its content, e.g. SpamAssassin (tm), not only miss 5 - 10% of real spam, but also incorrectly block 1 - 2% of legitimate emails.

Since SPAMSteward does not use content filtering based on "obvious" words and short phrases, it is much less likely to block legitimate emails. It can even be used by medical and legal organizations in which legitimate emails might discuss prescription medication, mortgage rates, profanity, and sexual terms.