§ 5 of the Telemediengesetz (German) lists what, for instance, website providers have to include in the typically called Impressum of the website.
The second sentence of (1) is:
Angaben, die eine schnelle elektronische Kontaktaufnahme und unmittelbare Kommunikation mit ihnen ermöglichen, einschließlich der Adresse der elektronischen Post,
Which according to cgerli.org (PDF) translates to:
details which permit rapid electronic contact and direct communication with them, including the electronic mail address,
Does the term elektronische Post (which translates to electronic mail) necessarily mean email (via SMTP)?
Of course one would immediately think of email (and some might use this term as synonym for "E-Mail", but it’s not really idiomatic), but then why doesn’t it say "E-Mail" or "SMTP"?
Because it doesn’t explicitly say so, my assumption is that it doesn’t have to be an email address, but just some address that allows to communicate electronically. Like a term for a category of communication protocols (i.e., protocols which allow to send messages in electronic form) instead of refering to the specific SMTP. (Which would make sense, because email might lose popularity, and then the law wouldn’t have to be updated.)
So, must it be an email address (RFC 6068) or may it be an address for a different protocol that allows to send/receive messages in the Internet?