Catfishing is a guessing game built from Wikipedia articles. Given a list of all the categories that an article belongs to, you must guess which article it's describing.
The original game was invented by Sumana Harihareswara, and consisted of reading aloud the category sections of Wikipedia pages to other players in the same room. This site merely automates the process, assigns a scoring system and gives it a silly name - you can either play it solo, or sit around with a few friends and see who gets the right answer first.
Anyone can add an article through the box at the bottom of the screen.
Articles are only accepted if they have four or more "useful" categories, after discarding
all the in-house Wikipedia categories and any "giveaway" ones (those
that contain
a word that's also in the name of the article).
This stopped working at some point when the API changed. It's not currently possible to add new articles.
You should mark an article as 'stupid' if it somehow doesn't make any sense, has a giveaway category that hasn't been filtered, or if the categories are too broad to be able to pin it down to the single answer (particularly if the answer you were thinking of would fit, but was wrong). Flagging stupid articles helps us keep the game interesting for everyone.
As of April 2007, there's a new scoring system. You'll gain and lose points for each question you answer, according to how difficult other players found it. If only 25% of players got a question right, you'll get 75 points if you can get it right (for knowing such an obscure thing), and lose only 25 for getting it wrong. If 99% of people got it right, you'll only get 1 point for knowing it yourself, but lose an entire 99 points for not knowing it.
All category data is taken from Wikipedia, licensed under the GNU Free Documentation License, and is rereleased under that same licence. The curmudgeonly catfish image is taken from the Mediaeval Woodcuts Clipart Collection.