Ubuntu Stack Exchange is a community driven Q&A site for both Ubuntu users and developers, currently in public beta. The idea is simple: you post a question and wait for the answers; users can then upvote the answers and the person who asked the question can also mark one of the answers as "best answer"! So far I noticed the answers have a really high quality so if you can't find the answer to your question(s), you may want to try the Ubuntu Stack Exchange!
Besides the help you give/get, the website is also fun and engaging: you get points when your answer or question is upvoted, you get badges when you perform a certain task and so on - and all these make your overall reputation increase.
StackApplet is a simple GNOME Panel applet which checks your Stack Exchange reputation every X minutes and displays it on the panel. StackApplet works with any Stack Exchange website and in fact, it can display your reputation across multiple websites at once.
Besides displaying your reputation, StackApplet also notifies you when comments are posted to you.
Download StackApplet (Ubuntu .deb)
[image credits: StackExchange]