Good point. I bet, though, that creating an account there triggers heavy-duty authentication.

And that reminds me. I recently tried to create a ProtonMail account via Tor. But they wouldn't activate it without mobile and credit/debit card numbers. Ironic, no? And yes, I do get that many jerks have misused ProtonMail accounts.

Edit: I take that back about Facebook. Via the onion, it just wanted an email address to authenticate. I'm impressed.