Small bumps on certain keycaps to help touch-typists find the home keys (ASDF and JKL;) without looking. They are nearly always on the "F" and "J" of a QWERTY and the "5" of a numeric keypad. The Macintosh, perverse as usual, has them on the "D" and "K" keys.

This term is based on the vernacular American expression "as useful as tits on a boar" (or boar-hog, bull, bullfrog, or many other variants), meaning "not useful".

[Jargon File]