So Verizon is adding an "Advertising Header" to outbound web requests. AT&T is "testing" a similar system. The basic premise is it uniquely identifies your device to websites you visit. Those sites can then provide Verizon (or AT&T) with this identifier and in exchange for money, they can get some personal information about you. So far it looks like just demographic and geographic data, but could be expanded to anything they know about you.
Verizon has some ability to opt-out, but only to the monetization, not to the adding of the headers. AT&T has the ability to opt-out on each device. They also claim to change the header every 24 hours as a way to provide some anonymity to customers, but that would only affect sites who are not paying AT&T money. It is unclear what data AT&T has for sale currently, but more details will arrive once their system moves into full production.
You can test to see this working on your devices if you are on either of these carriers by visiting the site below, but must do so over cellular (turn off WiFi).
http://lessonslearned.org/sniff
More details of the Verizon system, along with opt-out information:
http://www.wired.com/2014/10/verizons-perma-cookie/
Technical details of Verizon's system:
http://webpolicy.org/2014/10/24/how-ver ... der-works/
Details of AT&T system, along with opt-out information:
http://www.forbes.com/sites/kashmirhill ... artphones/
In previous statements, Sprint has made statements against this sort of thing, so it will probably only be a short amount of time before they implement something. T-Mobile has not made any statements about anything like this. I tested devices on both Sprint and T-Mobile and did not see any headers added.
Verizon adding "Perma-cookie" to web requests, AT&T testing
Re: Verizon adding "Perma-cookie" to web requests, AT&T test
I don't see anything on my Titan via AT&T.
Re: Verizon adding "Perma-cookie" to web requests, AT&T test
Maybe they are not testing you yet. Or they are starting with LTE. If only James read the forum still...