gettalong/kramdown — pull request #11 by tillda (2012-07-05 13:46:35+00:00)
Title: Adds the ability to offset levels of all <Hx> headings so the markup doesn't have to start at <h1> as top header

This is suitable anytime you are not writing a whole document in Markdown but just a part of it. An example might be a blog post, where the h1 tag is generated elsewhere by the template system, or even the h1 is the site logo, h2 the article title (generated elsewhere outside the article) so the article itself uses headers starting at h3.