I came across a cool favicon hack recently called Tinycon, which provides a Javascript function to add a small alert bubble to a favicon image. You can see a demo of it in action at http://tommoor.github.com/tinycon/.
Basic usage is super simple:
[sourcecode lang=”javascript”]
Tinycon.setBubble( 6 );
[/sourcecode]
sets a favicon alert bubble with the number six in it.
After looking at this I was surprised that Gmail hadn’t done this already. For that matter, perhaps the Google Chrome browser could provide some native functions to make it perform even better.
Code for Tinycon is available at https://github.com/tommoor/tinycon under the MIT open source license.