I've just spent an hour or so cobbling together a rudimentary browser extension, which does quite simply provide notifications of new posts and comments. It leverages Maki's built-in routable WebSockets, but doesn't provide much more – any further improvement would be appreciated!
I'm using a new library called Kango, which lets me write the code once and deploy an extension to each of the major browsers. I've uploaded an official version to the Chrome Web Store, but no other locations, as I have not tested them. Help here would also be appreciated!