spamblock

/spamblok/ , n. [poss. by analogy to sunblock] Text inserted in an email
address to render it invalid and thus useless to spammers. For example, the
address jrandom@hacker.org might be transformed to
jrandom@NOSPAM.hacker.org. Adding spamblock to an address is often referred
to as munging it (see munge ). This evasion tactic depends on the fact that
most spammers collect names with some sort of address harvester on volumes
too high to de-mung by hand, but individual humans reading an email message
can readily spot and remove a spamblock in the From address. Note: This is
not actually a very effective tactic, and may already be passing out of use
in early 1999 after about two years of life. In both mail and news, it's
essentially impossible to keep a smart address harvester from mining out the
addresses in the message header and trace lines. Therefore the only people
who can be protected are third parties mentioned by email address in the
message not a common enough case to interest spammers.