I hope that's not a metaphor for the, uh "seduction" performance of some gamers.
Anyway, here's what SJGames has to say in its new announcement.
Let's look at an analogy. You know how the GURPS Basic Set has rules for combat, right? Well, gamers who love combat options have helped make GURPS Martial Arts, GURPS Tactical Shooting, and GURPS Gun Fu some of our most popular releases. Each one of those supplements augments the core combat systems with expanded info and new possibilities.This is great news for gamers, especially GURPS gamers. To me, the GURPS line looks a bit like the rim of Burning Wheel, spread out over several books rather than chapters.
GURPS Social Engineering works the same way, adding options and rule systems for various interpersonal interactions. Think of it as "Martial Arts for the social arts."