According to Network Observations:
Verizon Wireless is mailing a notice advising wireless subscribers that if they fail to Opt Out within 30 days, Verizon will begin SELLING their Customer Proprietary Network Information (CPNI) to “third parties and affiliates”. CPNI information includes all the calls you place or receive on your cell phone (along with date, time and call duration). Verizon intends to allow “targeted ads” created by their affiliates sent to your phone.
Like Network Observations points out, most people throw away all the flyer insert garbage in their monthly bill and don't pay attention to the inserts. Hmm, couldn't the FBI and CIA skirt the whole FISA court warrant thing and simply pay Verizon a nominal advertising fee for access to ALL of Verizon's customer information? Like say $0.00000001 per phone record? Then the FBI or CIA can use their super computers to track dialing patterns to find terrorists without having to fight the ACLU over disclosing secret court orders. The FBI and/or CIA would be a bona fide paying customer with no need for a FISA warrant. Of course, this only gives them phone records, not entire customer conversations. And I'm sure there must be some legal precedent that would make this illegal. Still fun to hypothesize all the ways the government can invade your privacy though.
More likely the way it will work is that you pay Verizon and Verizon handles the display of ads on your phone, audio ads, etc. and they won't give away your private phone dialing habits. Of course, the CIA could ask to send ads to anyone making lots of calls to Afghanistan and Pakistan - assuming you must be a terrorist - and then send an ad stating, "This is the CIA. We're onto you. If you are a jihadist, quit now while you're ahead or Gitmo will be your new home." Might scare off a few dumb jihadists. Of course this method stinks of profiling. Can't have that now, can we?
In any event, if you are upset over Verizon revealing confidential customer info to advertisers in an opt-out policy, you can check out an open letter to the FCC asking to close the loophole.