The Archive Formerly Known As Cathouse
This refers to the alt.folklore.urban archive at http://www.urbanlegends.com/ (and http://www.tafkac.org/ these days), second only to Snopes.com as an online repository of information about urban legends and related lore. The archive used to be stored at cathouse.org, hence the name.
Where Snopes is something like an encyclopedia of urban legends, combining stories, debunking or supporting evidence, etc. in a standard form, TAFKAC is more anarchic. It is broken down into particular urban legends the same way Snopes is, but tends to be a simple compilation of the archivists' notion of the most significant and/or best-written AFU posts on the subject. I go to Snopes if I want a definitive summary answer for my own curiosity or to enlighten someone propagating a legend, but to TAFKAC if I want in-depth discussion or just random amusing commentary. In a world where the speed of communication means I can get forwarded half a dozen different unverified stories I've never heard before in a day, both are indispensible.
Since TAFKAC is associated with AFU as such rather than just urban legends per se, it also contains a significant number of pages that are about other topics that often come up on the newsgroup for whatever reasons, or about the newsgroup itself. The AFU FAQ, which contains information about the mores of the newsgroup as well as an extensive collection of one-line summaries of urban legends and AFU's assessment of their voracity, is hosted here.
A word of warning: if you get into the habit of replying to forwarded legends and hoaxes with appropriate Snopes and TAFKAC cites, people will quickly stop sending these things to you, but they won't necessarily stop believing them themselves or forwarding them to others.