A Python-Markdown preprocessor extension to ignore html comments opened by three dashes and any whitespace prior to them. I believe pandoc has similar functionality.
<!-- This is a standard html comment which will remain in the output. -->
<!--- This is a markdown comment which this extension removes. -->
pip install git+https://github.com/ryneeverett/python-markdown-comments.git
>>> import markdown
>>> import mkdcomments
>>> comments = mkdcomments.CommentsExtension()
>>> markdowner = markdown.Markdown(extensions=[comments])
>>> markdowner.convert("""\
... blah blah blah <!--- inline comment -->
...
... <!---multiline comment
... multiline comment
... multiline comment-->
...
... even more text.""")
u'<p>blah blah blah</p>\n<p>even more text.</p>'
In order to render markdown comments, you must *(a)*use them in an html block (which are not processed as markdown) and *(b)*escape the brackets so the browser won't think they're html comments. E.g.:
<pre>
<!--- meta markdown comment -->
</pre>