> It's almost never actually an outage impacting all of FAANG at once.

Exactly. If you click through down detector when things are _up_ you'll see people still complaining that $site is down. Could be a local power outage or even a flaky connection in their own home.

Down Detector is one of many signal sources and should have a "credibly" score associated with it that's proportional to the number of people complaining that something's down.