WASHINGTON — In the months and early years after 9/11, FBI agents began showing up at Microsoft Corp. more frequently than before, armed with court orders demanding information on customers.
Around the world, government spies and eavesdroppers were tracking the email and Internet addresses used by suspected terrorists. Often, those trails led to the world’s largest software company and, at the time, largest email provider.
The agents wanted email archives, account information, practically everything, and quickly. Engineers compiled the data, sometimes by hand, and delivered it to the government.
Often there was no easy way to tell if the information belonged to foreigners or Americans. So much data was changing hands that one former Microsoft employee recalls that the engineers were anxious about whether the company should cooperate.
Inside Microsoft, some called it “Hoovering” — not after the vacuum cleaner, but after J. Edgar Hoover, the first FBI director, who gathered dirt on countless Americans.
This frenetic, manual process was the forerunner to Prism, the recently revealed highly classified National Security Agency program that seizes records from Internet companies. As laws changed and technology improved, the government and industry moved toward a streamlined, electronic process, which required less time from the companies and provided the government data in a more standard format.
The revelation of Prism this month by the Washington Post and Guardian newspapers has touched off the latest round in a decade-long debate over what limits to impose on government eavesdropping, which the Obama administration says is essential to keep the nation safe.
But interviews with more than a dozen current and former government and technology officials and outside experts show that, while Prism has attracted the recent attention, the program actually is a relatively small part of a much more expansive and intrusive eavesdropping effort.
Americans who disapprove of the government reading their emails have more to worry about from a different and larger NSA effort that snatches data as it passes through the fiber optic cables that make up the Internet’s backbone. That program, which has been known for years, copies Internet traffic as it enters and leaves the United States, then routes it to the NSA for analysis.