Little Outliner is a new editor from Dave Winer that automatically saves text locally. The HTML5 web app is a super simple, super straightforward way to create outlines.
Here's a quick how-to for using Little Outliner. You can expand and collapse headlines hierarchically, and move things around with your mouse. For example, you press return to make a new bullet point or hit tab to move one over. Basically if you've ever used a text editor, Little Outliner will make sense to you. [Little Outliner h/t @tcarmody]