Track your StackExchange reputation, get notified of new comments and answers with StackApplet.
It is, as the name implies, an indicator-applet for StackExchange (including askUbuntu). You can add as many userid’s as you like and the applet will will conveniently and unobtrusively check for and alert you to updates at a user-configurable interval. You can also choose the icon (dark or light) and whether the app launches on start-up.
Version 1.4 has just been released and can be downloaded @ launchpad.net/stackapplet/1.4/1.4/+download/stackapplet_1.4.0_all.deb
Once installed it can be launched via Applications > Accessories > StackApplet.