@nvraemdonck I write j12t@social.coop on my business card. Web page. FediForum notes, whatever.
You read it, paste it into your favorite messaging app (like gmail, or Mastodon) and send me a message.
Why should you have to care that SMTP is different from ActivitiyPub? Or know that either of them exist?
@J12t @nvraemdonck si please enlighten me. If I send myself an email to my mastodon address I will receive that message here?