Toward a Better Markdown Tutorial

What is the real problem?

Is it:

* People don't know Markdown because they haven't heard of it

* People have heard of it, but don't know how to use it.

* People know how to use it, but don't know what formatting methods to use (e.g. what should be bold, italic or underlined)

* People know how to use it, but don't know that it's supported on the site they are using.

You can probably think of more points to add to the list, but this seems to suggest a solution without a complete understanding of the problem, which is "Why do people not use Markdown?"