In case you missed it, there are many Mastodon apps for old computers from the 1980s & 1990s:
:apple_old_logo: #AppleII
https://www.colino.net/wordpress/en/mastodon-for-apple-ii
:apple_old_logo: #AppleMacintosh (pre-OS X)
https://github.com/smallsco/macstodon
:commodore: #Commodore64
https://github.com/Havoc6502/MOStodon
:amiga: Commodore #Amiga
https://github.com/BlitterStudio/amidon
:ms_dos: #MSDOS
https://github.com/SuperIlu/DOStodon
:IBM: #MVS
https://github.com/mainframed/BREXXTODON
:Palm_OS: #PalmOS
https://github.com/knickish/heffalump
:windows95: #Windows95
https://github.com/meyskens/mastodon-for-workgroups
@FediTips How would one connect a C64 to the internet?