Markdown is a simpler way to format text. It's easier to read and write than HTML — so you can focus on your words, not on your formatting.
Markdown for MeFi is a browser plugin that brings Markdown to your comments and posts on MetaFilter.com.
Use asterisks to make bold and italics.
To actually surround text in asterisks, use backslashes.
Links go in footnotes.
Numbered links are quick and easy: [Google]
Naming your links helps keep them organized: [Yahoo!][yahoo]
You can also put your links inline. Use parentheses, not square brackets.
To make a block quote, begin a paragraph with >.
*The Lottery*, by Shirley Jackson, begins:
> The morning of June 27th was clear and sunny, with the fresh warmth of a full-summer day; the flowers were blossoming profusely and the grass was richly green.
* Asterisks at the start of a line make bullets
* Be sure to leave a space after the asterisk
1. Numbered lists go like this
2. Don't forget the period after the number
2. Your numbers don't have to be in order
3. So this will be item number 4
It's still beta software, so there are almost certainly bugs.
When trouble occurs, Markdown for MeFi will attempt to save your work by switching back to editing in HTML (the classic MeFi way). But if you're writing a massive treatise, maybe copy and paste a backup to another app, just in case.
Markdown does not yet work in the edit window; you always switch back to HTML there.
Everything you could already use on MetaFilter, but easier. Links, bold, italics, blockquotes, lists, and more. See the guide.
Some kinds of formatting, like small text, don't have a Markdown shortcut. So just use HTML tags like usual. (You can always use HTML instead of Markdown, if you want.)
Markdown for MeFi doesn't let you use formatting that you couldn't already use on MetaFilter. So there are still no tables, headings, or blink tags.
This is an open-source project: suggestions for improvement and contributions are totally welcome. The source code is on GitHub.