“We could of course update the domain that the sign talks to but luckily the domain that the sign communicates to by default was available for purchase.”
NYCTrainSign sold Raspberry Pi subway clocks for anywhere from $100 to $600 against a $150 bill of materials, then went silent in early 2018 and told customers to dispute the charge. Its signs still phone home to a domain anyone can buy. Chung bought it and can run arbitrary commands on every sign still in the field. When an IoT company dies, its fleet goes to whoever pays the registrar first.