Internet-delivered TV is the new front in the war for the attention span of Americans.
Netflix is following the drama House of Cards with four more series this year. Microsoft is producing programming for the Xbox video game console with the help of a former CBS president. Other companies, from AOL to Sony to Twitter, are likely to follow.
The companies are creating networks for television through broadband pipes and giving rise to new rivalries - among one another, as between Amazon and Netflix, and with the big but vulnerable broadcast networks as well.
"These are the very first lab tests in a very grand experiment," said Jeff Berman, the president of BermanBraun, a media company that makes programming for NBC, HGTV, AOL and YouTube. The competition has only just begun. Amazon is making pilot episodes for at least six comedies and five children's shows, with more to be announced soon. Sometime this spring it will put the episodes on its Amazon Prime Instant Video service and ask its customers which ones they like.
Netflix has been ordering entire seasons of its shows without seeing pilots first. Reed Hastings, Netflix's chief executive, said last week that House of Cards, the political thriller starring Kevin Spacey and Robin Wright, had been a "great success" for the company. Its next program, a horror series called Hemlock Grove from the film director Eli Roth, premieres in April.
The trend may inflame cable companies' concerns about cord-cutting by subscribers who decide there's enough to watch online.