Aptly named after the puzzling, unwanted meat product, spam (as
in "scam" or "sham") is Net-speak for unsolicited junk email. Spammers
love email because it costs next to nothing to send so they can
harass the world with limitless buy-this-stuff email (usually selling
smut or a program that generates more spam). Spammers will often
offer you the option of removing yourself from their emailing list.
But more often than not they use non-functioning return email addresses
or anonymous remailers so it's difficult to staunch their ever-steady
flow (though recent legislation has been passed outlawing this behavior).
However you're not helpless: Tools like spam-filter programs and
a spam-abuse hotline (spam.abuse.net) do provide recipes for cooking
spam.