Arizona's state Court of Appeals has upheld online consumers' right to privacy, in what appears to be the first ruling of its kind in the state.

What it means, the court said, is police and government agencies cannot use the users' information to learn who they are or where they live, without first having a search warrant and showing suspicion of criminal activity.

It is significant because federal courts in the past have ruled that when people volunteer their information to an internet service they give up their right to a "reasonable expectation of privacy."

The ruling stems from a Pima County case where a police detective found the IP address of a suspected pedophile through a federal subpoena that led to the man's exact home address.