The New York Times nails it:

As it happens, the three head honchos of Tapout, while they’ve never been fighters, did in fact train in martial arts. And of course they are hardcore fans. They started peddling branded T-shirts nearly a decade ago, when mixed martial arts was at its most marginal, and supporting fighters when mainstream brands steered clear. In a Barnumesque bid to get attention at matches, they developed outrageous (and preposterous) personas, calling themselves Mask, Punkass and Skyscrape, wearing glam-rock/hoodlum costumes and behaving more like mascots than entrepreneurs. Today they’ve become stars themselves, hunting for new fighting talent on a reality show on the Versus cable network; it’s a rare five seconds that goes by without a Tapout logo in view.

Tapout has now been profiled everywhere from BusinessWeek to CNBC. But evidence of mainstreaming and talk of palatability aside, the illicit air that clings to mixed martial arts is almost certainly part of the attraction. The sport’s most demonized era happened to coincide with the cult popularity of the movie “Fight Club,” which posited underground fist-fighting as a kind of therapeutic tonic for the numbing effects of consumer culture. It reportedly inspired real-life fight clubs — a response that is, of course, not for everybody. But the general idea of living on the edge, of a no-holds-barred struggle with an unambiguous result, appeals to many, and is just the sort of thing a brand like Tapout can offer indirect access to: not the life, per se; just the style.