Changing the title bar is ineffective; you either make the title blink between two states which is a blaring annoyance and terribly distracting (GChat), or you just add a modest little (1) that is hard to see (Facebook). I think the favicon is much better suited for this function; it conforms to what people are used to with mobile phone UI.
However, the problem with this library is it has to follow the limitations of favicons' dimensions. I think there should be an open standard for having alert badges like iPhone and Android phones put on top of home screen icons. The browser distributer could design theirs to match the UI so people could recognize them, and they could be allowed to extend just 2 or 3 pixels past the normal favicon boundaries to grab attention without being annoying or invisible.
You can tell when people want something when they're settling for several make-shift approaches at it within limitations.