But secrecy around the programs has meant even basic questions are still unanswered. Here's what we still don't know:
Has the NSA been collecting all Americans' phone records, and for how long?
It's not entirely clear.
The Guardian published a court order that directed a Verizon subsidiary to turn over phone metadata -- the time and duration of calls, as well as phone numbers and location data -- to the NSA "on an ongoing daily basis" for a three-month period. Citing unnamed sources, the Wall Street Journal reported the program also covers AT&T and Sprint and that it covers the majority of Americans. And Director of National Intelligence James Clapper himself acknowledged that the "collection" is "broad in scope."
How long has the dragnet has existed? At least seven years, and maybe going back to 2001.
Senate Intelligence Committee chair Dianne Feinstein, D-Calif., and vice chair Saxby Chambliss, R-Ga., said last week that the NSA has been collecting the records going back to 2006. That's the same year that USA Today revealed a similar-sounding mass collection of metadata, which the paper said had been taking place since 2001. The relationship between the program we got a glimpse of in the Verizon order and the one revealed by USA Today in 2006 is still not clear: USA Today described a program not authorized by warrants. The program detailed last week does have court approval.
What surveillance powers does the government believe it has under the Patriot Act?
The Verizon court order relies on Section 215 of the Patriot Act. That provision allows the FBI to ask the Foreign Intelligence Surveillance Court for a secret order requiring companies, like Verizon, to produce records 2013 "any tangible things" 2013 as part of a "foreign intelligence" or terrorism investigation. As with any law, exactly what the wording means is a matter for courts to decide. But the Foreign Intelligence Surveillance Court's interpretation of Section 215 is secret.
As Harvard Law Professor Noah Feldman recently wrote, the details of that interpretation matter a lot: "Read narrowly, this language might require that information requested be shown to be important or necessary to the investigation. Read widely, it would include essentially anything even slightly relevant 2014 which is to say, everything."
In the case of the Verizon order -- signed by a judge who sits on the secret court and requiring the company to hand over "all call detail records" -- it appears that the court is allowing a broad interpretation of the Patriot Act. But we still don't know the specifics.