Oh here, let me run it down real quick. You don't even need to be an expert.
Tracking cookies, browser fingerprinting, and ISP-level monitoring logs everything you do.
Various consumer database warehouses hoover up the data for resale/targetting by ad companies
Hint: once a business has it, at a minimum the FBI/CIA/Government has it. Likely, they've been hacked by China and Russia too.
In addition, the CIA/FBI run ISP-level and DC-level monitoring/hoovering.
Finally, there is no oversight. Either the FBI will cookie cutter whatever request they need after the fact to the rubber-stamp-anyway kangaroo oversight "Court", or they won't even bother. The CIA doesn't even need to care. The only limitation of widespread abuse is some sense of patriotism in the CIA/FBI, and of course that is pretty simple to frame/justify as needed.
The bottom line is that there is a 100% turnkey total information awareness infrastructure for any authoritarian regime that takes over the US government (see: Iraq war, false flag attacks, McCarthyism, etc). They know everyone you communicate with, your political views, your buying habits, and they will soon have AI software to maximize usitlization of the firehose for profiling, reeducation camps / gulags, and the like. The US government can deny you civil rights by declaring a US citizen an enemy combatant, and are more than willing to setup concentration camps for immigrants, and therefore "terrorists".