Everything around you with a microphone or a speaker collects audio 24/7. Smart phones, dumb phones, flip phones, tablets, IPads, televisions and so on. Video too. With some devices it’s done even when they’re off. Everything is collected from everybody. The data is warehoused in bulk. If and when an interest is taken in a person software can be used to scan for specific words, phrases, etc. within set time frames.
Take up Navajo or something if you want to have a private conversation.
Then there was the guy who figured out how to remotely control an ATM machine and somebody’s pacemaker. Somehow he died of a remotely controlled heart attack while still in his 30’s.
Then there was the guy writing about a BIG story for the Rolling Stone. He was concerned that his car had been tampered with. Somehow he died when his car careened off the road and into a tree. Somehow it exploded before it hit a tree.