I can't vouch for the source, but then, who can for this sort of thing?
They went after -- and I know this because I had my hands literally on the paperwork for these sort of things -- they went after high-ranking military officers; they went after members of Congress, both Senate and the House, especially on the intelligence committees and on the armed services committees and some of the -- and judicial. But they went after other ones, too. They went after lawyers and law firms. All kinds of -- heaps of lawyers and law firms. They went after judges. One of the judges is now sitting on the Supreme Court that I had his wiretap information in my hand. Two are former FISA court judges. They went after State Department officials. They went after people in the executive service that were part of the White House -- their own people.
This is exactly the reason we don't -- or didn't, until recently -- allow government to collect data without a warrant: it is inevitable that it will be abused. The source hints at data collection on Obama (from the Bush years), at least one Supreme Court justice (which raises all sorts of interesting questions about the Roberts vote switch on Obamacare), and god knows what else.
One of the problems with a system like this, that is designed to collect everything and then only reveal limited amounts when a particular number or data point becomes "interesting", is that everything you've done in the past becomes fair game when your number becomes "interesting".