They are partially right. Tracking down a number that is listed and comes from a land line phone is very easy to do. All you need is the phone number and you can simply type that number into most any online phone search or even a regular search engine. You will find all the information you need about the identity of the caller.
A call from a cell phone is another matter. In order to successfully find out who is behind these calls you will need to make use of one of the reverse cell phone lookup directories. Such directories are a relatively recent development. They contain powerful data bases that contain information on well over ninety per cent of all the currently activated cell phone numbers in use today.
A successful search will give you the identity of the caller, his or her current billing address, and other information you may want to know. These reverse look ups are private and confidential. No one need ever know you made such a search. If you suspect your spouse of running around behind your back, this is an effective way to learn just who keeps calling them.