By now it's established fact that your cell-service provider keeps a log of where you are and what you say, 24 hours a day, and this information will probably be retained by the NSA for a long time.
Some think we're getting dangerously close to 1984. If, say, Sprint were to start a campaign with slogans like "We don't spy on you", would that entice you to switch to such a provider?
Relevant links:
https://www.eff.org/deeplinks/2011/03/what-location-tracking-looks
https://www.eff.org/issues/nsa-spying
http://www.aclu.org/national-security/doe-v-holder