Will apps that don’t burn through your data plan destroy the Internet or save it?

Wireless service provider T-Mobile began offering its customers an alternative. Under a free feature on some plans, T-Mobile users can now stream music services like Pandora, iTunes Radio, Rhapsody, and Spotify all day long without having to worry about sapping their data caches.

T-Mobile calls it "Music Freedom," and it's part of a quiet but powerful global trend.

There is a trade-off for consumers, though. In return for low-cost service, users are, in some cases, being corralled into a limited view of the Internet. Rather than wandering freely from site to site, they have gained gatekeepers who have power over what they see.