A sliver of a woman's face punctuated with an arresting green eye: Just one of the unprecedented number of billboards blanketing Hollywood to pump the primetime fall season. Not to mention splashy print ads proclaiming "Smart is the new sexy" ("The Big Bang Theory") and "Tall, dark … and immortal" ("Moonlight"), among other catchphrases.

Seems network honchos and their marketing mavens are leaving nothing to chance in driving as much sampling as possible to their upcoming fall hopefuls.

And no wonder.

Out of 30-odd new primetime contenders, only half a dozen are likely to catch on. As a result, a greater proportion of marketing budgets has been earmarked for what brass believes to be the best bets of the season.

Thus Ben Silverman at the Peacock has his eye cocked for "Bionic Woman"; CBS is plumping for "Cane" and "Moonlight"; and ABC is touting its "Big Shots" and "Dirty Sexy Money." (Fox will largely idle along until "American Idol" in January.)

Marketing mavens at the nets have been some of the first to intuit that the country is no longer an old-style melting pot: We've morphed into a nation of niches.

The trick for these marketing folks is to reach, and intrigue, as many of those segments of the population as makes sense for any given show. (In this respect, CBS is arguably taking the biggest gamble in tilting its shows to attract auds outside its traditional demo targets.)

While marketing ploys have moved with the times, other things have stubbornly stayed the same. Year after year, the nets say they're fed up with the existing economic model and the same old way of doing things — launching dozens of shows all at once, few of which ever stick, but all of which cost an arm and a leg.

A year-round season? It never quite materializes. This summer was once again reality and reruns, so much so that cable outclassed the broadcasters. "Weeds," "Saving Grace," "Damages," "Army Wives" and other originals once again narrowed the ratings and quality gap with the Big Four.

"Used to be, clients would stare blankly if we advised them to do a cable show; now they're clamoring for these roles," as one Endeavor agent put it to me last week.

Making matters trickier this time, several primetime pick-ups had trouble getting out of the box. Creative differences plagued "Bionic Woman"; "Cavemen" had trouble coming up with a civilized story line; the "Pushing Daisies" start-up phase was like pulling teeth.

Still, it can't be said broadcasters aren't making some headway. Since few under 30 and virtually no one under 18 is watching scheduled television per se, forward-thinking nets are making their key shows available on as many platforms and under as many different price models as they can dream up.

"Digital is not yet the tail that wags the dog, but it's sure making the dog bark," is how one network exec described it. He also said it will become clearer over the next six to nine months just how big a stream these new ancillaries have become, if for no other reason because the labor talks will demand it.

Every network has a different tilt — price points, exclusivities, ad avails, revenue splits — when it comes to putting their shows online. But all of them are starting to see the pennies add up.

Several hundred million dollars in 2008 at each of the networks, this exec hazarded.

Not a humongous sum, but nothing to sneer at either.

In the meantime, there's "foreign."

Established juggernauts like the "CSI" franchise, "Lost" and "Without a Trace" are minting mucho moolah abroad — and in ever stronger currencies.

Sophomore sensations like "Heroes," "House" and "Criminal Minds" are also gathering steam. To wit, a busload of the "Heroes" ensemble on a recent international promotional tour was waylaid by a surge of adoring fans in, of all places, normally snooty Paris.

If those heady prices for U.S. shows hold, the foreign market may just sustain the domestic TV biz until digital comes to the rescue. But the latter had better be soon.

Elizabeth Guider can be reached at elizabeth.guider@hollywoodreporter.com.