The Tom Cruise-Katie Holmes divorce has provided A-list fodder for fanzines in the past two weeks, a vivid supermarket-line reminder that, even in the digital age, celeb magazines are still a force.

However, the relationship of showbizzers, PR execs and celebrity journalism continues to evolve. The Internet, with its endless hunger for showbiz gossip, consumes a disproportionate amount of time for publicists, but it’s still the old-fashioned magazine that’s the Holy Grail.

To be sure, print magazines relying on Hollywood star power have suffered. For example, In Touch and Life & Style each experienced a 48% drop in circulation since 2006, according to verification service Audit Bureau of Circulations (ABC). For In Touch, that meant a circulation drop from 1.27 million in 2006 to 663,870 last year.

Two exceptions to this trend are US Weekly, which gained circulation, and the venerable People Weekly, where slippage was minor; its category-leading circulation of 3.57 million last year is off just 5% from 2006, per ABC.

With the economy slumping and online competition mushrooming, things have clearly changed. “It’s a different world, and you have to understand the consumer doesn’t exist in a vacuum,” says David Perel, exec VP of digital content at magazine publisher American Media and managing editor and exec VP of Radar Online. “The common theme in both (the print and online) worlds should be reader engagement. We have to have the consumer engaged in the product, but it’s tougher to do that in print.”

Last year, entertainment publicity and marketing company Falco Ink stopped its longstanding courier delivery of key print publications to its office at the Toronto Film Festival. “Before, clients weren’t happy if a story was online-only and it didn’t make print,” says Janice Roland, co-CEO of Falco. “Not every story makes a print edition, and that’s another reason it’s more important. And personally, I feel something’s more important if it’s in print. You can hold it in your hands.” But, she says, that’s changing in the world of celebrities and gossip.

Still, most celebs and their publicists consider print magazines to be the favorite landing spots. “Whether 100,000 or 1 million people are reading about them … the point is somebody is reading, and these magazines are quite visible in supermarkets and discount stores where millions of women congregate,” says Al Lieberman, executive director of entertainment media and technology at NYU’s Stern School of Business.

At any given moment, there are only a handful of movie star celebs who can sell magazines: Right now, it’s TomKat, Angelina Jolie, Robert Pattinson-Kristen Stewart, and Jennifer Aniston (along with perennial fave Princess Di).

Otherwise, celeb magazines have created their own world of stars: Kim Kardashian, Paris Hilton and other reality TV celebrities.

Reality stars are willing to work hard at promotion and exploit their fame and “everyman” appeal.

“Reality TV celebs remind viewers of the guy who lives down the street who is an ex-Marine and just home from Iraq, or someone who serves them coffee at Starbucks,” says Hollywood reality TV publicist Charlie Barrett, whose work spans NBC’s “Unsolved Mysteries” to Fox’s “Cops” to CBS Television’s “The Amazing Race.” “The audience doesn’t relate as well to film stars, who live in a far-off fantasy world and whose life is unattainable.”

So box office winners like Will Smith, Adam Sandler and Meryl Streep, and TV actors such as Mark Harmon and Ed O’Neill are big stars in their own realms — but not in the world of celebrity gossip. (Some performers, including Ashton Kutcher, Oprah Winfrey and Jennifer Lopez, straddle both worlds.)

Movie stars can be found on the covers of fashion glossies such as Vogue, In Style or W. And Hollywood celebs are still big attractions online, where their lives and foibles feed the insatiable appetite of a vast array of entertainment news, reviews and gossip sites that range from gossip blogs, to movie-centric websites to vertical sites devoted to horror, sci-fi and indie films, among others.

Of course, the websites of print publications are also destinations.

A major plus for online media is its interactivity, which, for example, allows consumers to post movie content on social pages to share with friends and spark discussions. Another advantage: It lets marketers instantly connect to members of such orgs as, say, a dog-lovers club, a car aficionado group or a nonprofit (as in the case of “The Lorax”) and access their mailing lists.

Michael Nyman, co-chairman and co-CEO of publicity firm PMK*BNC, observes that online offers new ways in which information gets distributed and amplified. But online also carries new risks, because cyberspace is a wide-open realm with none of the time-tested professional standards of print publishing. Anyone with a nasty streak or an axe to grind can post snarky personal comments about celebrities or criticisms of entertainment products . And some fulminate just to get attention.

“If it’s so completely ridiculous, you let it go,” says Cindi Berger, PMK*BNC’s other co-chairman and CEO. “You can’t respond to every Internet rumor. If we did, we’d be up 29 hours a day. Whether we do (decide to respond) depends on the nature of the story and if it gets traction.”

Print still offers some editorial control for PR professionals, and celeb fanzines have a long life beyond the supermarket, since they can sit on a coffee table or in a salon or a dentist’s office waiting room for weeks at a time.

For now, print and online co-exist. “You want a combination,” says Shannon Treusch, co-CEO of Falco Ink. “You need everything if you’re going to make a dent in the vast popular culture.”