It's one thing to read about the click farms, but nothing can prepare one to actually see the videos of them in action - just visceral. It has an eerie Matrix-like feeling to it.
13 sec video of a Chinese click farm (quite loud):
https://twitter.com/mbrennanchina/status/1072114511212109824
10 sec - thousands of phones (not loud):
https://twitter.com/mbrennanchina/status/1148447866366464000