Hey kids, welcome to the world of MarkdownMe. This here site is a web service, a RESTful one I guess, meant to be consumed by Ajax and other programmatic means rather than by human beings. Feed it some Markdown syntax, and it will give you HTML.
To use: send a POST request to http://markdownme.appjet.net/to_html with one parameter, named markdown, that contains the Markdown text you'd like to convert to HTML. You'll get back bare HTML markup, not wrapped in a document element or anything, that corresponds to the Markdown you sent.
You can test our converter here via a form that basically uses the exact same mechanism (a POST request with a single param - well, the button adds another param, but it's ignored).
We're using Attacklab's excellent Showdown library to convert the Markdown.
OMG that means some other server is seeing my text!!!
That's right, Sparky. But if that poses a problem for you, there's an easy four-step solution!
Click the "Source" link down there in AppJet's footer for this page.
Click "Clone This App." Name your version something like "sparkys-markdown."
Before you publish your app, have a look at the URL listed near the top of the source. Load that up and see if it meets your privacy needs. If you prefer, you can replace it with a copy of the Showdown library that you trust. (Hint: follow the link above to Attacklab, download the library, and just throw it up on a free web host somewhere - once AppJet has served your app's front page just one time, you can take it down.)
Tell AppJet to publish the app. Voila, your own Markdown web service!
Of course all that assumes that you trust AppJet. If not, you have problems I can't solve.
Enjoy in good health,