I haven't posted anything lately, so I thought I should at least try for once-a-month posting...
A few months ago (April) I somehow discovered Yahoo Answers.
Being a librarian, and living with a Boy Scout complex, I immediately began to help people by researching answers online.
My profile can be found here which includes the various answers I've posted.
I'm proud of my 1600 points, but I have been slacking a bit lately... usually I answer a few at work while I wait for my computer to process files, or I spend a few hours on the weekend helping people.
The mathematics questions are the most fun, as they are more of a puzzle than a question. I try to be vague... instead of just giving the answer, I show how to solve it. Sometimes, my answer usually just gives the first step, then "solve for x".
A LOT of questions get repeated... some are nothing more than simple self-esteem or dating questions. Some sections tend to attract trolls and other extremes of human behavior, but that's the Internet for you... One can rate each answer with an UP/DOWN vote, and Yahoo does sometimes pull offensive questions (sometimes while I'm answering them!) so it there is some remedy.
The interface is quite easy to use... I recommend the site.