I self-host and my server runs at about 3% of what my aircons consume on a summer day.

It’s just one CPU, a PoE switch and some spinning drives. There seems to be an awful lot of waste in computing these days. Just don’t do wasteful things on the server like VMs, containers and desktops.

We need email. It’s one of the few protocols that are 100% in the user’s control. I run my own mail server. I can’t do the same for whatsapp.

We’ve added a lot of checks to email (SSL, DKIM, DMARC, SPF) so it’s very easy to identify spam these days. It’s also easy to avoid giving any two companies the same email address. That’s something much harder to avoid with a phone number.

For 2FA, per-account email addresses and authenticor apps are the best approach for privacy.