Turning on iTV

Roku sells a $99 player that links to the Netflix service. LG offers a similar option, but it works through a Blu-ray disk player. Tivo has forged links for all its digital video recorders with Amazon's video service, Rhapsody's music service and photo sites such as Google's Picassa.

Startup Vudu's box links to its own movie service, built up from its direct proprietary deals with studios. Apple TV relies primarily on links to iTunes.

"The thing is, you have limited selections of content in systems that only work with certain TVs and Internet connections—there are too many constraints," said Perlman.

An industry group such as the Consumer Electronics Association could play a critical role in defining the platform, even as it helps set expectations for HDTV, Doherty said. "We need a coherent industry understanding that OEMs, content providers and retailers can point to and say, 'This is Internet TV,'" he said.

The time is ripe. Today's new sets are all digital. Analog broadcasts will go off the air completely in the United States in February. Meanwhile, a growing collection of Web video sources is driving new use patterns.

"I have a lot of college-age friends who have no plans to buy a TV," said Perlman. "Everything they watch is online."