[miguelos]

That's exactly what I'm planning to build! I'm not sure if I should go hybrid or all-in.

By hybrid I mean that people could receive regular human-readable emails, but senders could include a small url or tag that links to the semantic information (it could be an event invitation, receipt, valid email confirmation, password changing, task proposal, marketing offer, flight information, etc.).

The "smart" email client could then automatically interpret semantic emails, and act accordingly. It would also hide those emails, and only show you the relevant notification.