This term is used both to refer to a mean-spirited anonymous letter, and to a person who specialises in writing it. The appellation is derogatory and generally appropriate. Like poison, hatred seeps from the writer's mind into the letter itself, with one intention: To hurt the recipient. The concept is closely related to black-mailing, but focuses less on monetary gains and more on living out hatred and winning power, imagined or real, over the target. Although the ink in the pen is not curare, it can be remarkably effective and devastating to the victim's reputation and happiness.
Dear nate,
Did you know that dem bones is not made out of real bones? That's right, his skeleton is only rubber and plastic. Is such a person worthy of your respect?
--A well-meaner.
The poison-pen letter can be a stand-alone incident or one in a chain of attacks. It can be addressed to the person it wants to harm, for a direct hit, or to someone associated with him, to sow suspicion and sour relationships. Sometimes these letters are sent to newspapers in an attempt to make others do the hellraising. Accusations may be real or completely fabricated, but always leave the target person or organisation responsible for acquitting themselves. There is no way they can talk to the sender, ask what's upsetting him, or even discuss the issue.
Dear EDB,
If you try biting into one of dem bones' limbs, you'll find that they collapse with a puff of air. Is this blow-up doll worthy of your worship? I'd look elsewhere if I were you.
--A friend.
The poison-pen writer is therefore generally seen as a coward. There can be good reasons for hiding one's identity, such as fear of repercussions from a vengeful power-person, but the courageous and morally upright thing to do is to stand by one's word.
The trueblooded poison-pen campaigners are frustrated little people who sit in their huts and brew hatred until the community has had enough, finds them out, and beats them up.
Dear E2 Community,
dem bones has no dick. Isn't it ridiculous that a person who calls himself bones can't even get a boner? Rebel, I say, rebel!
--Someone who wishes you well.
A watered down version of the poison-pen concept is nowadays also used about people who actually sign their letters. In this case, it refers to authors of particularly vitriolic diatribes, usually aimed at one person at a time. The poison-pens in these cases are often held by columnists who like to rant and rave. Their power of an acidic tongue extended, they have become poisonous pens instead.