We have mentioned Tinycon some time ago, which allows the addition of alert bubbles and changing the favicon image. Now, we got Piecon, which is a tiny javascript library for dynamically generating progress pie charts in your favicons.

Piecon has been tested on Chrome 15+, Firefox 9+, Opera 11+. And the library falls back to title updates for Internet Explorer 9 and Safari 5+. It is licensed under the MIT license. It is pretty handy for web applications I think.

Requirements: JavaScript framework
Demo: http://lipka.github.com/piecon/
License: MIT License