T-Mobile US last night announced a "Music Freedom" program that will exempt certain music streaming services from counting against the monthly data limits that the so-called "uncarrier" imposes on its customers.

"Beginning immediately, T-Mobile’s Simple Choice customers will now be able to stream all the music they want from all the most popular streaming services, including Pandora, Rhapsody, iHeartRadio, iTunes Radio, Slacker, and Spotify—without ever hitting their high-speed 4G LTE data service [limits]," T-Mobile said. "Music services from T-Mobile partners—Samsung’s Milk Music and the forthcoming Beatport music app from SFX—will also stream without data charges for T-Mobile customers."

Companies don't have to pay T-Mobile for the privilege of not counting against 4G data limits.

"T-Mobile is not paid by the streaming services," a company spokesperson told Ars. Even for partners Samsung and SFX, "nothing related to music streaming is paid," T-Mobile said. T-Mobile is polling customers about which services they would like added to the unlimited streaming program.

T-Mobile's decision not to send a bill to the streaming companies is in contrast with AT&T, which this year started turning its data caps into greater profits by charging content providers for the right to serve media without chewing up consumers' monthly data limits.

Technically, T-Mobile Simple Choice customers can use unlimited data but are throttled after using up their 4G allotments. Individual plans start at $50 a month for 1GB of 4G data and unlimited talk and text. After hitting the 4G limit, customers have to make do with paltry "2G" speed—128Kbps at the most—for the rest of the month unless they buy more high-speed data.

Exempting popular content from data caps is no doubt a good thing for consumers who subscribe to those services—although unlimited data for everything would be better. Although it's not a paid service, the T-Mobile program is drawing opposition from network neutrality proponents who say the program nonetheless favors big content providers at the expense of smaller ones.

T-Mobile is launching its own music service in partnership with Rhapsody, so unlimited data for other music streaming companies was needed to show that T-Mobile isn't favoring its own service over others.

Even so, T-Mobile is "choosing winners and losers online," argued Michael Weinberg, VP of consumer advocacy group Public Knowledge. In an e-mail to Ars, he wrote:

At its most basic, net neutrality is about preventing ISPs from choosing winners and losers online. This is exactly what T-Mobile is doing with this announcement. Having created artificial scarcity by throttling customers after they use a certain amount data, T-Mobile is now opening up special lanes for a handful of music services that presumably are either already popular or have someone on staff with an existing relationship with T-Mobile. This immediately creates two classes of music services—those that can get you throttled on T-Mobile and those that cannot. These classes create a barrier to any new entrants. If they can get enough customers to vote for them, they can get into the unlimited lane, but now they have to attract those customers as a service that will get them throttled. Furthermore, there are plenty of niche services that are important to their users but may never meet critical mass to get into the T-Mobile unlimited lane. Even a quick survey of people in the office this morning identified music apps from local radio stations like WFMU and KCRW and bigger subscription services like those from Google and Rdio that don't make the cut. WFMU and KCRW might be popular by community radio standards, but they are unlikely to be a position to get into the T-Mobile unlimited club. More generally, this plan highlights again how data caps are currently being used by ISPs to manipulate their customers' experience online. Whether it is Comcast exempting its own video services from a data cap or T-Mobile blessing a handful of music services, these caps allow ISPs to push people toward some services over others. That fundamentally changes the nature of competition online.

Free Press Policy Director Matt Wood agreed, telling Ars that "even if all music apps are on equal footing, they are advantaged against other kinds of apps. That kind of favoritism skews innovation because it favors certain content, business models and technologies over others."

Creating data scarcity

The FCC is drawing up a new set of net neutrality rules after its previous ones were gutted by a court decision, but the FCC's latest proposal largely exempts wireless carriers

T-Mobile's move to exempt certain kinds of services is a tacit admission that its own data limits can be bad for consumers. Why should browsing the Web or watching video, but not listening to music, count against a user's data plan?

"The more practical present-day concern is about the data caps themselves," Wood said. "What's the justification for a cap if music can be so easily uncapped? Certainly not congestion. Any time a carrier says hey, pay us a little more or use a certain service and the data is free, then you have to think the cap is arbitrary in the first place."

T-Mobile CEO John Legere said in the company's announcement that he is "personally outraged at the way the other guys are using the music you love to lure you into over-priced plans with sweet ‘promotional offers’ that quickly roll into higher prices or trigger those absurd overage charges. Music should be free of all that. Music should have no limits. So, beginning right now, you can stream all you want at T-Mobile from all of the top music services—data charges do not apply.”

According to a CNN article, "Legere dismissed concerns about Music Freedom's net neutrality implications, saying new services could be quickly included in the program."

We asked T-Mobile how it chose these particular streaming services and how other online services (whether music or otherwise) can join the unlimited data program. In response, T-Mobile pointed to the poll of consumers it is conducting to determine which other music services should get the unlimited data treatment. The poll offers a choice of Amazon Prime, Beats, Google's All Access, Grooveshark, Jango Radio, Last.fm, Rdio, Sirius XM, Sony Music, SoundCloud, and TuneIn Radio.

T-Mobile didn't say whether it will offer a similar program for non-music services.

"We started with [music] services that cover 85 percent of our customers but are allowing them to tell us what other services they want," a T-Mobile spokesperson told Ars. "It’s all about the customers for T-Mobile!"