What does a slash mean before a name signature in emails?

It is intended to suggest a signature as opposed to just the typed name. I suspect this practice derives from similar signifiers used in typewritten copies of legal documents. It also seems likely that it is related to the practice of using slashes to represent /italics/. The parallel with closing HTML tags () may also have helped to cement this practice as it is used at the end of an email. This seems like a more tenuous connection but it does account for the loss of the slash after the name. Another explanation for that could be that the email style is a blend of two common typewritten styles (see below). Email version: /John Doe Typewriter versions: s/John Doe /John Doe/