In Prison Break the National Security Agency's (NSA) Echelon program was mentioned. As mentioned in the TV-series the program is suspected to catch email traffic, faxes and phone conversations, not only as they say across the country, but across the world.
The European Parliament conducted an investigation against the Echelon-system in a periode between 1999 and 2004, the final report might be read at http://cryptome.org/echelon-ep-fin.htm. But what is this echelon thing?
In the greatest surveillance effort ever established, the US National Security Agency (NSA) has created a global spy system, codename ECHELON, which captures and analyzes virtually every phone call, fax, email and telex message sent anywhere in the world. ECHELON is controlled by the NSA and is operated in conjunction with the Government Communications Head Quarters (GCHQ) of England, the Communications Security Establishment (CSE) of Canada, the Australian Defense Security Directorate (DSD), and the General Communications Security Bureau (GCSB) of New Zealand. These organizations are bound together under a secret 1948 agreement, UKUSA, whose terms and text remain under wraps even today.
The ECHELON system is fairly simple in design: position intercept stations all over the world to capture all satellite, microwave, cellular and fiber-optic communications traffic, and then process this information through the massive computer capabilities of the NSA, including advanced voice recognition and optical character recognition (OCR) programs, and look for code words or phrases (known as the ECHELON "Dictionary") that will prompt the computers to flag the message for recording and transcribing for future analysis. Intelligence analysts at each of the respective "listening stations" maintain separate keyword lists for them to analyze any conversation or document flagged by the system, which is then forwarded to the respective intelligence agency headquarters that requested the intercept.
Here you can see a map of the listening stations
Now, many will probably say that its not a problem that the government conducts surveilance on them, as they have nothing to hide. If you just had this thought, please read the final report. Chapter 10.7. Published cases include some reading material for you. One case worth to mention is one of Airbus versus Boeing in 1994. Where NSA obtained "Information on an order for aircraft concluded between Airbus and the Saudi Arabian national airline" using the means of "Interception of faxes and telephone calls between the negotiating parties" with the goal of "Forwarding of information to Airbus's US competitors, Boeing and McDonnell-Douglas", which resulted in "The Americans won the contract (US$ 6 bn)"
Learn how to protect yourself, and visit secure-my-email.com