With Penthouse and Playboy making concerted efforts to legitimize their content beyond the centerfold to gear and gadgets, it's not surprising that part of this push has involved digital offerings. Digital magazine publisher Zinio has quietly launched something called Undercovermags.com, a sort of one-stop shop for such titles as Penthouse, Penthouse Letters, Swank and Celebrity Sleuth, many with subscription options that include video. Prices are steep — $49.95 for a subscription to Mystique? — compared to "legitimate" titles. And, not surprisingly, Zinio's branding is tucked away — the only way you'd know Zinio operates the site is via a pull-down menu to navigate to its other digital offerings. (Interestingly, Playboy — which Zinio offers, is not included in the Undercovermags site, but tossed in the pile of regular titles.)

Indeed, Zinio has tagged the site as "beta" and offers no press release — and, trust us, they would, if they wanted to promote it.

Which brings us to this question: If porn publishing — and, for that matter, digital magazines — strive to be seen as legit, why is it necessary to ply their wares undercover?