CBS recently hosted a trio of broadband chats heralding the return of its first-year series “Jericho.” Fans called in as if it were a radio show, addressing questions directly to stars and producers of the apocalyptic drama.

It’s a great idea in customer-service terms, even if only a small fraction of the show’s 10 million viewers avail themselves of the opportunity. Yet increasingly, networks are designing ever more elaborate means of catering to the cultish portion of a program’s audience — to the point where these fan-based flourishes hyper-inflate their relative value, potentially obscuring or distracting from the larger prize of attracting a mass audience.

Buoyed by their novelty, producer podcasts and online games, deleted scenes and character blogs have become all the rage. Still, this whole trend is bubbling along without much mind to its inevitable limits, as defined by the majority of consumers with little demonstrable appetite for chatting, playing along or making their own films using pre-approved toolkits.

As evidence, consider a new survey by Knowledge Networks/SRI, analyzing use of network Web sites. Despite the many new features available, the report notes, the most-used attribute “is quite pedestrian: checking the broadcast schedule” to see when shows are airing. By contrast, less than 5% of Web site users polled said they use the sexiest, most-discussed elements — among them podcasts and user-generated content.

“The lesson is a common one regarding technology — sometimes the most fundamental functions are the most valuable,” the study observed.

Networks are nonetheless forging ahead with gee-whiz add-ons to augment their shows. Sci Fi Channel, for example, has put together an online “video toolmaker” for fan(atic)s of “Battlestar Galactica,” allowing them to assemble personalized short films based on the interstellar soap by downloading canned visual and sound elements to blend with their own video.

Knowing that networks are notorious for chasing upscale demos, this sounds strangely counterintuitive — a come-on to computer-fluent young guys with way too much time on their hands. On the plus side, it’s a natural venue for ads touting Internet dating services.

It’s not just the vast reaches of space, though, where the cult component of primetime is seemingly running amok. Think about the energy ABC devoted to pumping up the volume surrounding “Lost,” creating Web sites and tie-in books sprinkling clues over which die-hard enthusiasts can obsess, containing details about the show’s Hanso Foundation or Dharma Initiative.

The producers, of course, were quick to stress they had no intention of taking their eye off the ball — that the show’s popularity made these ancillary elements possible, and keeping “Lost” fit and hardy remained Job One.

You have to wonder, though, if the excitement engendered by all these new toys didn’t divert attention marketingwise from the lion’s share of viewers, who don’t watch closely enough to differentiate between Hanso and Han Solo or the Dharma Initiative and “Dharma & Greg.”

Let’s be generous and say 5% of the population for any given show will eventually care enough to take advantage of and participate in various extras. While enhancing their experience and ardor certainly can’t hurt, there’s scant reason to believe that does anything for the 95% with their feet on the coffee table, or — especially for a marginally rated show — helps pad the overall numbers.

As savvy as TV marketers have become about creating tie-ins, they’ll also never be able to match the thrill of bottom-up movements and self-discovery. Indeed, an official sanction spoils half the illicit fun, which explains why the best gimmicks are often low-tech and fan-initiated, such as the drinking game that has sprung up around NBC’s “Heroes.” (Take a drink each time the Peter character brushes his hair aside, or Mohinder references “My father’s research.” Drunken hilarity ensues.)

Networks and studios also insist they still haven’t divined a way to siphon significant revenues from these sideshows, rendering them promotional at best — a “zero-billion-dollar business,” as the saying goes, much like the Internet circa 2000, right before the ceiling collapsed.

Catering to hardcore followings is fine, then, but only if the process recognizes that TV’s primary goal still involves attracting a mob. Because while cult fans might provide a show’s beating heart, programmers won’t be able to give them anything to be cultish about in the long run if there isn’t a crowd to go with them.

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