"Arrested Development," once on Fox TV, will have its new season streamed to subscribers of an online video service. Sam Urdank for Netflix

Internet-delivered TV is the new front in the war for viewers' attention spans.

Netflix, the online movie rental company, is following up on the $100 million drama "House of Cards," the political thriller starring Kevin Spacey and Robin Wright, with four more series this year. Microsoft is producing programming for the Xbox video game console. Other companies, from AOL to Sony to Twitter, are likely to follow. The companies are, in effect, creating new networks for television through broadband pipes and also giving rise to new rivalries - as between Amazon and Netflix and with the broadcast networks as well.

Amazon is making pilot episodes for at least six comedies and five children's shows. Sometime this spring it will put the episodes on its Amazon Prime Instant Video service and ask its customers which ones they like, then order full seasons of some of them.

Netflix has been ordering entire seasons of its shows without seeing pilots first. Reed Hastings, Netflix's chief executive, said that "House of Cards" had been a "great success" for the company. Its next program, a horror series called "Hemlock Grove," premieres in April.

Microsoft has said little about its plans. But all three companies are commissioning TV shows because they have millions of subscribers on monthly or yearly subscription plans. Though the shows may lose money in the short term, having exclusive content increases the likelihood that existing subscribers will keep paying and that new ones will sign up, bringing in more money in the long run.