SPAM (aka spam) is an acronym for Self Propelled Advertising Media. Its practitioners are the epitome of evil.
Spam\x99 is an utterly evil tasting processed meat product. It comes in a can.
Ambrose Bierce, in The Devil's Dictionary, notes the following:
Cabbage tastes evil when boiled. Especially when it's boiled with Spam\x99.
--Alex_Swavely?
I think "Self Propelled Advertising Media" is a Backronym (tm). Everyone knows the name came from the Monty Python skit, and was applied because of unsolicited commercial bulk email's similarity in the aspect of overwhelmingness.
--Steve_Dupree?