From May 17 to May 20 2024 the Institute of Electrical and Electronics Engineers (IEEE) in collaboration with People Centered Internet (PCI) is holding three events that will celebrate three 'Milestones' in the development of the Internet. The first Milestone celebrates the 50th anniversary of publication of an IEEE technical paper describing TCP, a
#Mail
Remember MCI Mail? You could could send hard-copy MCI Letter messages to postal addresses that were laser printed at an MCI Mail print site, placed in an envelope & mailed via the U.S. Postal Service.
I was an "early adopter" of this service (don't forget the stop bit!) I used it for work but my favorite use was to mail a birthday card I forgot to send since It was faster than snail mail. (We just called it mail!)
I see #VintCerf was involved in developing it. https://en.wikipedia.org/wiki/MCI_Mail