One of the nation’s biggest sellers of TV commercials thinks those types of ads do not belong when people use other kinds of screens to watch their favorite shows.

In a move that could add a new degree of complexity to the market for advertising associated with TV programs, 21st Century Fox says its FX cable network  will “no longer” sell standard commercials for digital and on-demand playback of its content, a new signal that viewers of TV shows have varying expectations for the way they experience commercials when using new ways to watch.

Fox Networks, which also includes Fox Broadcasting and Fox Sports 1, said that it intends to work to sell FX advertisers exclusive sponsorship of on-demand streams as well as thread “sequenced” creative executions through shows watched in streaming fashion. The hope, the company said, is that the effort will ” bring better attention and focus” to the ads that do appear in digital streams.

The offer comes after the company last week named a new executive, Joe Marchese, to lead ad sales efforts. Marchese is a digital-advertising entrepreneur whose company, TrueX, was purchased by 21st Century Fox in 2014  for about $200 million. In public appearances, Marchese often talks of how advertisers need to win consumers’ attention, rather than stealing it with old-school ad pitches that disrupt a content experience.

Simply put, the Fox offer recognizes what many network and ad executives already know: Digital viewers have long been accustomed to seeing fewer ads than they might deal with on TV, and would likely engage more with pitches that speak to them in while they are in the lean-in streaming experience rather than the lean-back living room milieu. Marchese and his team developed a product that allows digital-video users to choose to interact with a brief full-screen ad that typically offers an enticement or reward in exchange for the time granted to watch it, rather than having to endure the usual buffet of TV commercials that interrupt the content.

Fox’s idea has the potential to create new challenges for TV executives who are trying to devise ways to measure viewership of programs across different consumption points. GroupM, one of the largest media buyers in the U.S., is at present pursuing a methodology that would require TV networks to run the same “load” of ads no matter where the content is being seen, though executives have suggested they will be flexible in adopting a model.

The company also said it and NBC had agreed to use analytic data from Moat to measure attention to on-demand viewing. Fox Networks will guarantee portions of  ad campaigns against Moat data, and will offer data that could enable advertisers to tweak commercials on the fly, measuring sentiment that might give a sponsor the impetus to run a different commercial later in the day depending on what it learns about consumer attitudes at earlier times.