Hack value is the notion among hackers that something is worth doing or is interesting. This is something that hackers often feel intuitively about a problem or solution; the feeling approaches the mystical for some.
Doing something others think impossible, and doing it with finesse, cleverness, or brilliance implies the solution has hack value.
Picking a lock has hack value. Smashing a lock does not. Being the first to work out that super-cooling an unbreakable high-tensile steel lock with liquid gas making it possible to smash has hack value. And so on.
Proving Fermat's last theorem by linking together most of modern mathematics has hack value. Solving the four color map problem by exhaustively trying all possibilities does not. Writing a program to solve the four-color map problem exhaustively, however, does have hack value (as generating all the possibilities is itself potentially difficult).
The physicist Richard Feynman had a keen appreciation of hack value, and was a keen lock-picker. At the Challenger Space Shuttle accident inquiry, he performed a classic hack, demonstrating the potential of O rings for causing the disaster by freezing an O ring and showing its failure in front of a press conference.
