As a result, most T-Mobile customers can, starting Thursday, watch YouTube videos without using up their cellphone data.
YouTube, which is owned by Alphabet, didn't like that T-Mobile then delivered all video in DVD-level quality, which is worse than HD - even video from companies that hadn't joined Binge On.
YouTube, as well as others including digital-rights group Electronic Frontier Foundation, criticized this as throttling, which the government's net neutrality rules don't permit. T-Mobile CEO John Legere said in a video posted online that that charge was "a game of semantics" because customers could opt out and stream higher quality video if they wanted. Customers would use up more data if they did that.
Proponents of net neutrality, the concept that Internet service providers should treat all traffic equally, are concerned about efforts by T-Mobile and other ISPs, including Verizon, AT&T and Comcast, to exempt some video or other online activities from data caps. They worry that could lead to some Internet companies paying cable and phone businesses for better access to consumers, hurting other Internet companies that can't afford to pay. (T-Mobile doesn't charge video companies to participate in Binge On, however.)
T-Mobile has changed its service to appease YouTube. Now T-Mobile allows video providers to manage video streams themselves, which YouTube is doing. That helps YouTube make sure that video doesn't take a long time to load for viewers.
Video providers can also choose whether they want to be able to stream their video at a higher quality. If they do that, T-Mobile customers will have to use more data to watch it.
YouTube also said in a blog post that T-Mobile has made it easier for customers to turn off Binge On so that they can watch HD video.
T-Mobile said on Thursday that it has added some other, smaller video providers to Binge On as well. The program now has several dozen in all, but does not include Facebook or Snapchat, a photo and video app that's become popular with teens and young adults in the last few years.