Related Stories: ?TV Networks on the Web ?Local Broadcasters: The Net's Sleeping Giant

Although the practice of promoting Web sites on the air is relatively new, television allows for instant feedback of successes and failures, helping producers to quickly assess what works and what doesn't.  

"The more valuable a tie-in is to the viewer, the more immediate traffic results," says Katherine Dillon, vice president and general manager at ABCNEWS.com.  

An example of a valuable tie-in was when a "World News Tonight with Peter Jennings" story about toxins in soil ended with a suggestion that viewers go to ABCNEWS.com to enter in their zip codes and find out what dangerous toxins might be in the soil in their neighborhood.  

"Those calls to action really do produce traffic," says Dillon. More generic tie-ins, like displaying a general URL or saying 'visit us online,' don't necessarily drive people to their computers.  

"But we'll take it any way we can get it," she says. "Any traffic is good traffic."

Another approach, taken by PBS.org, is to run a "bug" interspersed throughout the program. "I don't know of many other [networks] that actually do that. We have been doing it this 'Frontline' season and, from what I understand, it's been very successful," says Rob Caskey, assistant manager of online communication at PBS.org.  

And, according to Caskey, the briefer the URL, the better.  

"It's 'PBS.org' for simplicity. Adding 'Frontline' is too long. We just send everyone to the homepage, and when a show's airing, we put a feature button on the homepage," Caskey says.

"Occasionally, people will have trouble navigating, but it's still more effective."  

The popular approach to nudging television viewers online uses a hard sell and a soft sell to build both awareness and traffic. But displaying a generic URL tagline or general reference to the Web alone does little for online traffic.  

"The more specific you can be, and the more tailored it is to the story, the better," says Lynn Povich, managing editor of East Coast programming at MSNBC.com  

"Tie-ins that solicit a response from viewers, like 'Log on and tell us your stories about the Vietnam War,' and items that add depth to a broadcast story are particularly successful," Povich says.  

For example, MSNBC.com recently posted Kenneth Starr's memo responding to the "Pressgate" article in Brill's Content magazine. "We promoted it saying, 'if you want to read the entire 18-page memo, go to our Web site.' That worked," Povich says.  

"What doesn't work are general ones. We have completely abandoned those. We say and show something that adds value," Povich says. ''For more info' just doesn't do it. The payoff isn't there."  

Sometimes what makes a tie-in successful may have more to do with the audience than the tie-in. George Jamieson, vice president of media relations and corporate communication at CNBC, says CNBC's audience is "watching with the idea of taking action."  

"People are looking for information they can use to manage their investments and make decisions on their financial affairs," he says.  

Keeping content current is very important, too, according to Povich.

Still, producers say the single biggest mover of television viewers to the Web remains breaking news.  

Beyond sharing anecdotal success stories, networks declined to share their Web traffic numbers. Indeed, unlike television, there has yet to emerge an industry wide standard to measure audience traffic on the Web. Without a ratings and share system in place, networks generally choose either to release Web performance data that appears in their favor, or decline to release it altogether.