Hello there! This is a sample post for gist.io, a super-lightweight writing soapbox for hackers.
Now look up. Further. Above the post title. See that grey text with the gist ID?
Now back to me. That grey text is a link! Open that sucker in a new tab to see the source for this post. Also, I'm on a horse.
This is a major heading
If you peek at it with a web inspector, you'll see that it is a second-level heading. You can use first level headings, but they'll look just like the second level ones, and the gods of the HTML5 outlining algorithm will frown upon you.