What is the proof that AWS is down? Functional monitoring of AWS by metrist.io (I'm a co-founder) shows no AWS problems. Downdetector is not a reliable source.
It's solely based off social media and user reports. It's the "smoke" in the saying "where there's smoke, there's fire" with the caveat that in some cases there's actually no fire even if there's a decent amount of smoke.
Downdetector relies on user reports, so e.g. if a user's ISP is down and they can't get to Facebook, they might report Facebook being down (or vice versa). DD spikes are typically indicative of _something_, but it's not always the actual down service.
Gotcha. Although for a spike this large (over 1000) for a tech service (AWS vs Facebook) I'd give some credence to it. It could be that everyone who reported AWS as down is running on Heroku. Definitely possible. For comparison Azure [0] and Google Cloud [1] have spikes under 30.
It can be useful, but you have to take it with a grain of salt. A perfect example is the recent Facebook (Meta) outage. When that happened, Downdetector showed that ATT, Verizon, and T-Mobile all had issues. They didn't, it was just Facebook and users mentioned or otherwise claimed that it was their mobile carrier.