Originated as a biker term used in two contexts:
1. Forever Two Wheels. A validation of biker culture, values, and of course, bikes.
2. Fuck The World. A rejection of non-biker/traditional values/laws of any kind.
According to people who should know, the first was the true origin of the term.
From a Hell's Angel working security at a Grateful Dead concert, when (stupidly) asked about the meaning of his FTW tattoo: "Forever Two Wheels".
Has since been appropriated by and attributed to everything from Hollywood Squares (For the Win) to Greenpeace: (Free The Whales)etc, etc, ad infinitum.