Presumably, a Markdown-enabled email client would display a pretty-printed version of an email it thinks is in Markdown. The output, not the input. Markdown is

Presumably, a Markdown-enabled email client would display a pretty-printed version of an email it thinks is in Markdown. The output, not the input. Markdown is no more text than HTML is. Which is to say, it is, but it also has more structure you can teach software to interpret intelligently. The only difference is that Markdown is 1) more human readable and 2) less standardised. I think reifying our social conventions for conveying formatting over plaintext so that software can understand it is an excellent initiative.