I saw this mentioned the other day on the "Smoked Hotdogs" thread, so I looked it up on Wikipedia. Here it is:
KISS is an acronym for the design principle "keep it simple and stupid", most commonly read as the backronym "keep it simple, stupid!",[1] or sometimes "keep it short and simple"[2] or "keep it simple and straightforward".[3] The KISS principle states that simplicity should be a key goal in design, and that unnecessary complexity should be avoided.
Some propose that it should follow its own advice by dropping the redundant letter and be just KIS, "keep it simple".[citation needed] Others believe that this final, essential point is the point.
Bearcarver