The history of email entails an evolving set of technologies and standards that culminated in the email systems in use today.
Hence it is that I cannot in any degree approve of those restless and busy meddlers who, called neither by birth nor fortune to take part in the management of public affairs, are yet always projecting reforms; and if I thought that this Tract contained aught which might justify the suspicion that I was a victim of such folly, I would by no means permit its publication.
SNDMSG (Wikipedia) SNDMSG was an early electronic mail program, chiefly notable because it was used to send what is considered the first networked email.