Suppose a telephone company maintained records on every telephone call it handled, showing the calling phone number; the called phone number; and the time, date, and duration of the call

What uses might the telephone company make of those records? What uses might commercial marketers make? What uses might a rival telephone company make? What uses might a government make? Which of those uses violate individuals’ privacy rights?

Possible telephone company use: Capacity planning; billing; ideas for new services.
Possible marketer use: Data mining to advertise to the caller/recipient.
Possible rival telephone company use: Market research to woo customers.
Possible government use: Looking for suspicious communications; criminal prosecution.