With the plugin enabled, every post offers the option to Edit with Barley, although merely visiting a post, or previewing a draft, is all that’s required to edit inline.
Post titles can be changed with a straightforward click and type. Categories, tags and the featured image can all be inputted via the slightly erratic, hovering bubble at the top-right of the content, made distinguishable by the tag icon it holds.
If you're a WordPress blogger (self-hosted), you'll love Barley for WordPress.
It will totally change the way you look at your site, particularly if you have a huge archive. I wrote about my initial experiences with the plugin here.
A week later, I'm even more enthused about it...