Kevin Smith likes to watch porn online, not to get his jollies but to marvel at how extreme the art of exhibitionist sex can be.

“I’m a morning porn peruser, and not for the titillation factor. I just find it interesting,” said Smith, whose latest comedy is “Zack and Miri Make a Porno,” the tale of best friends shooting their own skin flick to dig themselves out of debt. “I’ll go read Google news, I’ll go read Guardian UK, go read our Web site, and then if I’ve got nothing else, I will just peruse the porn sites, because it’s an ever-expanding world.”

“Just when you see the most outlandish clip you could ever see, somebody introduces something new. I just check in periodically just to see how far porn has gone in my absence,” Smith said after screening “Zack and Miri” for The Associated Press at his Los Angeles home last week.

Debuting Oct. 31, “Zack and Miri” stars Seth Rogen and Elizabeth Banks as lifelong buddies who have shared an apartment for years but never considered each other as potential mates.

Writer-director Smith — whose films include “Clerks,” “Dogma” and “Chasing Amy” — has taken two people who have yet to realize they’re a couple and cast them into a sweet little romance — with a whole lot of sex and swearing.

Profanity is almost a given for Smith, whose characters barrage one another with four-letter words.

“It turns some people off but that’s how mostly everybody I know speaks,” Smith said. “It’s kind of strange. Whenever somebody goes, `That offends me,’ I’m like, wow, what kind of weird, opposite bizarro frame of mind do you live in? Cursing is just so second nature, you don’t even think of it as cursing any more. It’s just your lexicon.”

At the outset of the new film, Rogen’s Zack and Banks’ Miri have known each other so long and so well that they’re almost like siblings. The twenty-something slackers blissfully share a dumpy apartment on which they’re far behind on the rent and utility bills. When the electricity is turned off in the middle of winter, they burn their unpaid bills in a garbage can for heat.

A chance encounter with a gay porn actor (Justin Long) gives Zack the notion that they could make their own sex flick to pay off their debts. When he and Miri add up how much money they could clear from one dirty movie, they wonder why everyone isn’t busy making porn.

“Because other people have options and dignity,” Zack concludes.

They recruit an amateur cast and crew to make their porno, among them “Clerks” co-star Jeff Anderson as “cinematographer” and Jason Mewes — Jay to Smith’s Silent Bob, the pair of stoners in most of his movies — as a well-endowed “actor.”

The cast also includes Craig Robinson as Zack’s co-worker and producer, “Superman Returns” star Brandon Routh as Long’s lover, and former adult-film star Traci Lords and current porn queen Katie Morgan.

The porn shoot becomes something of a loving, though lewd, re-creation of how Smith made his debut film, “Clerks,” at the New Jersey convenience store at which he worked.

“Basically, it’s a dressed-up version of making your first film. It just happens to be a porn film,” Smith said.

Just like “Clerks,” “Zack and Miri” initially was hit with an NC-17 tag by the ratings board of the Motion Picture Association of America. That rating prohibits anyone younger than 17 from seeing a movie.

Smith nipped and tucked the key objectionable segment, a comically over-the-top sex scene between Mewes and Morgan. But the ratings board held to the NC-17 designation, which Smith later got knocked down to an R rating after stating his case to the MPAA appeals board.

With the exception of one tender, tame sex scene, the porn action in “Zack and Miri” was meant to be outrageous, a commentary on the impossibly silly deeds in real skin flicks, Smith said.