Poe's Law is named after its author Nathan Poe, is an Internet adage reflecting the fact that without a clear indication of the author's intent, it is difficult or impossible to tell the difference between sincere extremism and an exaggerated parody of extremism.
The law and its meaning
Poe's law states:
"Without a winking smiley or other blatant display of humor, it is impossible to create a parody of fundamentalism that someone won't mistake for the real thing."
The core of Poe's law is that a parody of something extreme by nature becomes impossible to differentiate from sincere extremism. A corollary of Poe's law is the reverse phenomenon: sincere fundamentalist beliefs being mistaken for a parody of that belief.
A further corollary, the Poe Paradox, results from suspicion of the first corollary. The paradox is that any new person or idea sufficiently extreme to be accepted by the extremist group risks being rejected as a parody or parodist.
The statement called Poe's law was formulated in 2005 by Nathan Poe on the website christianforums.com in a debate about creationism. The original sentence read "Without a winking smiley or other blatant display of humor, it is uttrerly [sic] impossible to parody a Creationist in such a way that someone won't mistake [it] for the genuine article."
The sentiments expressed by Poe date back much further – at least to 1983, when Jerry Schwarz in a post on Usenet wrote:
Avoid sarcasm and facetious remarks.
Without the voice inflection and body language of personal communication these are easily misinterpreted. A sideways smile, :-), has become widely accepted on the net as an indication that "I'm only kidding". If you submit a satiric item without this symbol, no matter how obvious the satire is to you, do not be surprised if people take it seriously.
Another precedent posted on Usenet dates to 2001. Following the well-known schema of Arthur Clarke's Third law, Alan Morgan wrote:
"Any sufficiently advanced parody is indistinguishable from a genuine kook."
So if you are going to joke, emote or parody don't forget your emoticon or somebody may think you are serious!