Is Big Brother wiretapping the American populace as a whole?

Yes. Always expect that you're being monitored.
Do anything online and you leave an electronic signature that can be followed.

During my civilian career, there was no expectation of privacy as phone calls, emails, internet use were spot monitored, briefcases searched, etc. Even after being told they were being monitored, there were a bunch of folks fired, a lot of them for getting into pornographic websites. I was not doing anything illegal, and did not care except for the random drug tests, which were a pain.

Yes, and it has been going on for a very long time. At least the capability has been there for a long time.
The only limitation is the number of analysts available to find anything interesting.