I'm dealing with 2 problems with YOURLS in WordPress 3.3 that makes this plugin completely useless.
1. YOURLS plugin uses the admin bar to display the shortened URL. Since
Wordpress changed the method plugins deal with the admin bar in version 3.3, there is no longer Shortened URL button. Nor you can find the shortened URL anywhere.
2. I run my own YOURLS installation. If only the button was missing, I could find the shortened URL in the YOURLS admin panel. Turns out no shortened URLs are being generated, too. In that case, I don't know what changes in WordPress 3.3 helped cause that.