The WSJ is reporting that the NSA can actually reach and spy on more of the internet than it has publicly said. In fact, it looks like the NSA can reach roughly 75 per cent of all US internet traffic.
The WSJ writes:
The systems operate like this: The NSA asks telecom companies to send it various streams of Internet traffic it believes most likely to contain foreign intelligence. This is the first cut of the data.
These requests don't ask for all Internet traffic. Rather, they focus on certain areas of interest, according to a person familiar with the legal process. "It's still a large amount of data, but not everything in the world," this person says.
Basically, through these relationships with telecom companies, the NSA is potentially able to cover about 75 per cent of the US internet, because they represent 75 per cent of the US internet. The NSA has said it monitors 1.6 per cent of the world's internet traffic.
After getting traffic from telecom companies, the NSA then figures out which traffic to keep tabs on using "strong selectors", anything ranging from an email address to computer addresses that correspond to companies the NSA wants more info about can be a selector. This theoretically narrows down the amount of traffic that the NSA is actually 'monitoring'. Still, having the ability to reach 75 per cent of all US internet is impressively scary.