Pronounced "rote-13."A simple encoding scheme often used to scramble posts to Usenet newsgroups.
ROT-13 works by swapping each alphabetic character with another 13 characters removed from its location in the alphabet, so that a becomes n, and so on; numbers and punctuation are unaffected.
ROT-13 makes the article unreadable until the text is decoded and is often used when the subject matter might be considered offensive. Many newsreaders have a built-in command to unscramble ROT-13 text, and if you use it, don't be surprised by what you read. If you think you might be offended, don't decrypt the post.
You will also find other, inoffensive material encoded by ROT-13, including spoilers that give away the ending of a book or film and answers to puzzles or riddles.