The answerbag is an awesome site that collects questions and allows users to post answers. A community driven rating system evaluates the quality of the answers and generally seems to filter the noise from the signal quite effectively.
The questions range far and wide and the answers are typically succinct and accurate. Generally.
I had been consuming their RSS feeds (summary of feeds) for quite a while and found it to be an interesting way to throw some random bits o' information at my brain in the morning.
Now I am finding myself throwing out an answer or two and rating other folk's answers. Kind of fun.
Unlike answerbag, WikiPedia is intended to be an open content encyclopedia in many languages. It is truly an incredible resource.