How to determine a company's physical location

Companies that do business on the web often do not publicize their brick-and-mortar location.  The Consumerist offers this tip:

By law, any website that collects data from its users is required to post a privacy policy, and all privacy policies are required to display a physical address to send mail to.  You can also then use that address in databases to track down other contact information associated with it, like a live phone number.

A good tip to tuck away for possible future use.