Tinycon allows the addition of alert bubbles and changing the favicon image. Tinycon gracefully falls back to a number in title approach for browsers that don't support canvas or dynamic favicons.
Alerts in the favicon allow users to pin a tab and easily see if their attention is needed.
Look up and check out the favicon on this page to see the library in action on chrome and firefox.
Tinycon can be downloaded from the public repository on github.
Please use github to submit issues with Tinycon, or if you just want to say hey - i'm on twitter @tommoor