Actors having real sex in art-house movies. Erstwhile child star Lindsay Lohan appearing barely clad on the cover of her new album. Teenage girls strolling down Main Street USA attired in ''Porn Star" T-shirts. A bikini-wearing Jessica Simpson bumping and grinding in the music video for ''These Boots Are Made for Walkin.' " College-age women flashing for the ''Girls Gone Wild" video series with nonchalant exhibitionism. Not too long ago, pornography was a furtive profession, its products created and consumed in the shadows. But it has steadily elbowed its way into the limelight, with an impact that can be measured not just by the Internet-fed ubiquity of pornography itself but by the way aspects of the porn sensibility now inform movies, music videos, fashion, magazines, and celebrity culture. Even cooking shows on the Food Network -- the Food Network! -- contain distinct parallels with the cinematography, dialogue, and body language of pornography, according to an article wryly headlined ''Debbie Does Salad" in the October issue of Harper's magazine. Chances are the republic will survive gastro-porn. But on a more serious level, a growing number of critics are raising concerns about the way an X-rated atmosphere is making its way, in diluted but unmistakable form, into popular entertainment. ''The standards and aesthetics of pornography have really infiltrated the mainstream culture," says Pamela Paul, author of ''Pornified," which examines the role pornography plays in contemporary life. ''It's not just that the culture has gotten sexier. It's that the culture is directly referencing pornography."