[jimmydorry]

Email is decentralised if you ignore that 99% of email must go through the gatekeepers known as Microsoft and Google. Sure, anyone can spin up an email server, but either one of the gatekeepers can arbitrarily decide to reject all email coming from your small server and there is no recourse beyond begging them to reconsider.

[tehjoker]

The real infrastructure is the backbone providers and telecom companies. You can't do anything without them.