It would also raise new questions about how far Internet providers may take these exemption programs. By giving certain companies special treatment over the mobile Internet, T-Mobile could trigger additional regulatory scrutiny under the government's net neutrality rules.
Opponents of so-called zero rating have criticized the practice because it potentially allows wealthy companies to muscle their way in front of consumers at the expense of smaller rivals. Washington's net neutrality regulations are aimed at preventing that, although the rules don't explicitly ban zero rating.
Facebook co-founder Mark Zuckerberg has come under fire for his stance on zero rating internationally. He defended it in India this week in connection with Internet.org, the organization that provides free online access to health and financial services to residents of developing countries through a special app. Even Wikipedia offers a zero-rated service abroad. This business model can make it cheaper for low-income people to get online.
But developing countries are distinct from developed ones. Basic Internet access is prohibitively costly for many more people in the former than in the latter. So zero-rating carries very different implications there than it does here.