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.