Buried in the WaPo business section:
"That was my 'aha!' moment," Klein said. "They're sending the entire Internet to the secret room."
The diagram showed splitters, glass prisms that split signals from each network into two identical copies. One fed into the secret room, the other proceeded to its destination, he said.
"This splitter was sweeping up everything, vacuum-cleaner-style," he said. "The NSA is getting everything. These are major pipes that carry not just AT&T's customers but everybody's."
His first inkling that something was amiss came in summer 2002 when he opened the door to admit a visitor from the National Security Agency to an office of AT&T in San Francisco.
"What the heck is the NSA doing here?" Mark Klein, a former AT&T technician, said he asked himself.
A year or so later, he stumbled upon documents that, he said, nearly caused him to fall out of his chair. The documents, he said, show that the NSA gained access to massive amounts of e-mail and search and other Internet records of more than a dozen global and regional telecommunications providers. AT&T allowed the agency to hook into its network at a facility in San Francisco and, according to Klein, many of the other telecom companies probably knew nothing about it.
Read the rest here.