The New York Times continues to lead the pack on reporting on privacy and security issues. On Saturday, the NYT ran an article on the increasing frequency with which law enforcement are seeking information from internet service providers in connection with investigations of all kinds: Increasingly, Internet's Data Trail Leads to Court - New York Times.
As I have said here, if you don't need the data, don't keep it. That data can be stolen, compromised or you could find yourself an information collector for law enforcement and others. Responding to privacy incidents is costly and dealing with subpoenas is also expensive. Check out: The Canadian Privacy Law Blog: Don't keep the data that you don't need.