Whatever the NSA was doing in the way of warrantless snooping doesn't seem to have especially productive, at least according to the people on the receiving end:
"We'd chase a number, find it's a schoolteacher with no indication they've ever been involved in international terrorism - case closed," said one former F.B.I. official, who was aware of the program and the data it generated for the bureau. "After you get a thousand numbers and not one is turning up anything, you get some frustration."