Here’s a simple tip for using MarsEdit with Micro.blog. By default, formatting options in MarsEdit such as Bold and Italic map to HTML tags:
<em>. You can customize them to use Markdown instead.
Click on Format → Customize to bring up MarsEdit’s Formatting Macros window. Delete the existing Bold and Italic commands and click the “+” button to create a new one. For Bold, add “**” for the opening and closing markup and set the keyboard shortcut ⌘B. For Italic, use “_” and ⌘I.
Not everything in Markdown can be added to MarsEdit this way, but it’s nice to have a couple of the basics. You can also set the Preview Text Filter in the preferences window to Markdown.