/r9k/ is an imageboard where there are no exact reposts.

1. If you attempt to post something unoriginal, it is not posted, and you are muted temporarily.
2. The time with which you are muted for doubles with each transgression.
3. Each mute time is 2^n in seconds where n is the number of times you have transgressed. So, your mute time doubles each time you fuck up.
4. Backlinks, eg >>1, are not viewed by the robot. So "lolwut" and ">>2 lolwut" are the same post, in the eyes of the robot.
5. Gibberish at the end of a post to force originality may result in mod intervention (no BLOX posts please).
6. Images are NOT included in the filter, only text.
7. Your mute count slowly decreases over time.
8. You cannot post a picture without text.
9. Unicode is blocked. Sorry, too many exploits (Cyrillic letters, etc).
10. Posts require a certain minimum amount of original content in order to be posted.
11. Post sane, real content, well thought out replies, and mutes are unlikely.
12. The original algorithm was designed by XKCD:
http://blag.xkcd.com/2008/01/14/robot9000-and-xkcd-signal-attacking-noise-in-chat/