The secret life of your cellphone

[Commentary] Concerned that mobile phone networks are becoming surveillance tools, the American Civil Liberties Union recently asked hundreds of local law enforcement agencies whether they've tracked people's movements through their cellphones. Most of those that responded said they had, usually obtaining the information from mobile phone companies without a warrant. The practice has become so routine, the ACLU found, that phone companies are sending out catalogs of monitoring services with detailed price lists to police agencies. The alarming findings should persuade Congress to clarify that the government can't follow someone electronically without showing probable cause and obtaining a warrant.