The Ooma Blog has a short article that explains how anyone who knows your cell phone number has the ability to hear your calls, read your texts, and track your location (even if GPS is turned off). I suggest this article be required reading for anyone who is concerned about privacy and does not want anyone listening in.
The article is obviously designed to promote Ooma’s VoIP telephone service, which is encrypted. However, I have used Ooma for several years and love the service so I don’t mind the advertising.
NOTE: If you want low-cost telephone service at home or at the office, you might want to check out Ooma at http://www.ooma.com.
The article about cell phone privacy may be found at http://www.ooma.com/blog/who-can-listen-to-cell-phone-calls as well as in the infographic below.