I did a smidgen of research on this:
[i]ECHELON was reportedly created to monitor the military and diplomatic communications of the Soviet Union and its Eastern Bloc allies during the Cold War in the early 1960s, but since the end of the Cold War it is believed to search also for hints of terrorist plots, drug dealers' plans, and political and diplomatic intelligence.
The system has been reported in a number of public sources.Its capabilities and political implications were investigated by a committee of the European Parliament during 2000 and 2001 with a report published in 2001,and by author James Bamford in his books on the National Security Agency of the United States.
In its report, the European Parliament states that the term ECHELON is used in a number of contexts, but that the evidence presented indicates that it was the name for a signals intelligence collection system. The report concludes that, on the basis of information presented, ECHELON was capable of interception and content inspection of telephone calls, fax, e-mail and other data traffic globally through the interception of communication bearers including satellite transmission, public switched telephone networks (which once carried most Internet traffic) and microwave links.
Intercepting written but encrypted communications, and extracting information, probably did not wait long after the development of writing. A simple encryption system, for example, is the Caesar cipher. Electronic interception appeared as early as 1900, during the Boer War. The Boers had captured some British radios, and, since the British were the only people transmitting at the time, no special interpretation of the signals was necessary.[/i]
[i]The United Kingdom â?? United States of America (UKUSA) Agreement is a multilateral agreement for cooperation in signals intelligence among the United Kingdom, the United States, Canada, Australia, and New Zealand. It was first signed in March 1946 by the United Kingdom and the United States and later extended to encompass the three former British dominions .This was a secret treaty, allegedly so secret that it was kept secret from the Australian Prime Ministers until 1973.
The agreement established an alliance of five English-speaking countries for the purpose of sharing intelligence, especially signals intelligence. It formalized the intelligence sharing agreement in the Atlantic Charter, signed in 1941, before the entry of the U.S. into the conflict.[/i]
Cliff notes: Electronic interception systems have stalked electronic encryption systems like a spurned lover since the Boer War. The U.S, U.K., Canada. Australia and New Zealand have signed a treaty basically allowing each country to spy on themselves as long as the others know about it. In short, methods of intercepting e-messages have developed alongside actual e-messaging. It's no wonder that people can tag text messages so easily.
Echelon featured heavily in The Bourne Ultimatum. And people cat fight over political puppet shows when this is going on in the background...