spamblock /spam'blok/ 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.