Well, actually, they have been doing it for many years. But with cell phones, the call record includes the cell tower you are using, so your whereabouts can be easily tracked by time and location (within a mile, roughly). If telcos can access your phone's GPS location, your location can be recorded precisely.
According to MIT Technology Review, researchers and marketers are finding plenty of new uses for call detail records, or CDRs -- which allow them to study a mountain of user behavior data. That data can be used by researchers or city planners to study travel behavior -- but it's likely going to be a gold mine on the marketing behavioral front...
The telcos don't care about your privacy, and are quite willing to sell your personal information. With a publicly owned or controlled telco, we can prohibit such invasion of privacy and consumer manipulation.
Read the full story at dslreports.com