The Federal Electronic Communications Privacy Act (ECPA), which governs how law enforcement can access electronic data, was signed into law in 1986. The folks over on the Official Google Blog think it is time to update the law. Below is what they are proposing:
 

Specifically, we want to modernize ECPA in four ways:

• Better protect your data stored online: The government must first get a search warrant before obtaining any private communications or documents stored online;
• Better protect your location privacy: The government must first get a search warrant before it can track the location of your cell phone or other mobile communications device;
• Better protect against monitoring of when and with whom you communicate: The government must demonstrate to a court that the data it seeks is relevant and material to a criminal investigation before monitoring when and with whom you communicate using email, instant messaging, text messaging, the telephone, etc.; and
• Better protect against bulk data requests: The government must demonstrate to a court that the information it seeks is needed for a criminal investigation before it can obtain data about an entire class of users.