If you want to convert data exported from Wordpress.com into Markdown with front matter, you can use this program.
With XML data like this:
<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0" xmlns:excerpt="http://wordpress.org/export/1.2/excerpt/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:wp="http://wordpress.org/export/1.2/">
<!-- ... -->
<item>
<title><![CDATA[My Title]]></title>