Amazon Web Services is a cloud computing service which, to put it briefly, allows you to run websites. You could have a physical server rack in a datacenter near you, or spin up some servers on AWS (or Google Cloud, or Azure).
A lot of very large companies use it, including a lot of Fortune 500s for their ordinary company websites, as well as major web apps like Netflix, Reddit, Pinterest, Spotify, etc. And of course Amazon itself.
Now, those listed sites probably would get a call if something were to happen, but too many HN startups are running on AWS accounts linked to the founder's gmail and personal shopping account. Imagine if a dispute over a return of some counterfeit junk bought on Amazon by some CTO suddenly took down all of Netflix...
