Infographic timelines the history of surveillance by the U.S. government

An infographic was recently published detailing the United States government's surveillance in a timeline. It's a good refresher of the last hundred or so years on the subject. Here's the intro:

With the revelation that the federal government, through the National Security Agency, has been collecting phone and Internet records of U.S. citizens in the name of preventing terrorism, Americans are wondering whether private communication exists. Let’s explore how this surveillance works and the history of domestic spying programs (because, let’s face it, they’re not new) and how, even with broader knowledge of the government’s activities, a minority of Americans oppose such programs.