Markdown was based on the "syntax" already being used informally in emails and on IRC. So the author did do some searching to define the syntax.
I don’t like many parts of markdown either (like the syntax for bold), but those were also IIRC already being parsed by some IRC clients before Markdown was specified.
> Markdown was based on the "syntax" already being used informally in emails and on IRC.
News to me :-/
> So the author did do some searching to define the syntax.
I recall using tin/rtin in 1995, and people used the org mode syntax for italics, underline and bold (not that it made any difference). Same with plain-text email (I used elm, then pine, then mutt). Same with IRC clients - convention was the org mode syntax, not the markdown we have today.
The very first time I saw '**' for bold was in setext, circa 2004. People weren't actually using setext though; they were using *some text*, _some text_ and /some text/.
In short, no, I don't believe that the authors did any research. I think what happened is that they saw something like setext, though "great idea, lets run with that!", and did so.
I don’t like many parts of markdown either (like the syntax for bold), but those were also IIRC already being parsed by some IRC clients before Markdown was specified.