The first minimalistic markup I encountered was the WikiWiki way as described at http://www.usemod.com/cgi-bin/wiki.pl?TextFormattingRules and other wikis.

I almost don’t bother to mention “BB-code” from PHP-BB which seemed not much more than a way to encode certain smilies.

Then I encountered StructuredText in 2004 when a co-worker started promoting Plone (a CMS based on Zope using Python.)

That opened up a Pandora’s box, and now I am aware of MarkDown and Textile.