Mr. Wurtzel has found that most consumers — at least 75 percent in his studies — prefer to watch higher-quality versions of episodes via their trusty TV sets. They make distinctions between dialogue-driven comedies like “The Office,” which are better suited to laptops and iPods, and special-effects-laden dramas like “Heroes,” which look better on a big screen, he said.
For a variety of shows, the Web proves valuable as a time machine, permitting users to catch up on missed episodes. The Web site for “Jericho,” a show that was canceled by CBS but revived last year because of Internet-savvy fans, had roughly 1.3 million video views in the first week after the show’s second-season debut on Feb. 12. Less than half of those views were of the premiere episode; the rest were from viewers catching up on the first season or sharing clips.
In addition to tracking the episode views, CBS measures the amount of online conversation happening about shows.
“We’re still midstream,” said Nina Tassler, the president of CBS Entertainment. “We’re still learning about people’s behaviors and we’re still learning about what shows really resonate with an online audience.”
Other consumers use the Internet to discover new shows. Jason Kilar, the chief executive of Hulu, heard rave reviews of the NBC comedy “30 Rock” last year but never took the time to watch the show until he could stream it online. After one episode, he was hooked.
“After I put my kids to sleep and I have a few minutes to spare, I’m able to catch up on the show,” he said. “It provides an opportunity to both sample and consume content without having to schedule the DVR, without having to think about the on-air schedule.”
For the time being, broadcasters are harnessing the audience interest in different ways. Hulu content is widely distributed on MySpace, Yahoo , AOL and a variety of other sites. Similarly, CBS has chosen to syndicate its shows across a range of sites called the CBS Audience Network.
ABC, a subsidiary of the Walt Disney Company , has been more guarded with its content, making episodes available for streaming on only its Web site. Mike Shaw, the president for sales and marketing for ABC, said ABC.com has served up more than 220 million ad impressions, or views, in the last six months, up 188 percent from the same time period a year earlier.
And in the last month, all the broadcast networks have added classic series to their Web sites, making shows like “Star Trek,” “MacGyver,” “The A-Team” and “I Dream of Jeannie” available online. For companies that have sold all their available advertising space, tapping into their show libraries creates new opportunities.
“We would love to have more inventory,” Patrick Keane, the chief marketing officer at CBS Interactive, told reporters last week. “The advertisers are raring to go.”
"Our challenge with all these ventures is to effectively monetize them so that we do not end up trading analog dollars for digital pennies,” Mr. Zucker said, calling it the No. 1 challenge for the industry.
Some people pay for episodes via Apple’s iTunes Store and Amazon’s Unbox service, but many more appear to be watching streams of free, advertising-supported episodes on Web sites. In a closely watched effort, NBC Universal and the News Corporation are about to introduce their joint streaming site, called Hulu.
One piece of good news for the networks and advertisers is that viewers are more likely to remember ads on the Internet versions of TV shows, partly because the commercials are less numerous and more demographically aimed online, according to many studies.
For the moment, at least, conventional wisdom holds that the television and the Internet will essentially merge in the foreseeable future. Already, the hardiest of online viewers are letting PC screens replace their TVs altogether. Others are merely letting broadband connections supplement their digital video recorder.
About six months ago, Peer Gopfrich, a screenwriter in Los Angeles, bought a high-resolution liquid-crystal display TV screen for his living room. Around the same time, he discovered that the television networks were offering some shows online in a high-definition format, so he hooked an old computer up to his TV monitor and started streaming. Mr. Gopfrich’s computer became a free and seemingly endless source of on-demand television.
“All of a sudden, we could watch pretty much every popular show we wanted, when we wanted, in high definition in our living room,” he said.