Will Fly: The bear subculture of gay men has existed since the 1980s and has *many* Web sites, mailing lists, magazines, books, clubs, bars, etc. The definition of "bear" is disputed (and that of "cub" even more so), but typical components of the image are a beard, hairiness, an ample belly, working-class origin, and an easygoing attitude.

In the name of the site you cite, "Woof" alludes to an interjection expressing appreciation of an attractive bear. If by chance someone woofs you on the street, you should understand it as an intended compliment.