[bitcrazed]

You think there weren't codes of conduct back in 1983? ;)

[recursive]

All those years, people thought MS was hostile to open source, but their commitment was right there all along, in the GW-Basic code of conduct, with a link to their website too!

[4cao]

Markdown itself is from 2004 but the .md extension/suffix wasn't used for it until sometime later (not really sure where it appeared first).

[tjalfi]

MDCD[0], an open source DOS archiver, used the .MD extension in 1988.

[0] https://www.sac.sk/download/pack/mdcd10.zip