In his original documentation for Markdown, Gruber acknowledges an number of influences. Mostly common plaintext email conventions of the time, but also Setext,

In his original documentation for Markdown, Gruber acknowledges an number of influences. Mostly common plaintext email conventions of the time, but also Setext, reStructuredText, and more by name. He did not include reference to org-mode, so he probably did not know of it at the time. (Although maybe Aaron Swartz was familiar with org-mode, and provided cross-pollination?) Most likely as you mentioned, md and org both evolved independently from similar ancestors https://daringfireball.net/projects/markdown/syntax https://daringfireball.net/projects/markdown/syntax