Quora is nice. Don't go to Yahoo Answers. People report you for the simplist things while trolls run rampant. You can get your email account deleted for getting reported too many times. I got reported quite a few times. One of the things I got reported for was answering a question that asked what I did to be less harmful to wildlife, thereby reducing my human footprint. I simply gave a list of regular things I did. Reported. :P
In Quora, you get points, even for asking a question. The points are given when people vote up your question or answer. People also post pics and blogs there that other people also vote up. You can ask other people to answer but it costs you points per person. It is really fun. I haven't decided which site is more fun- this one or that one. I think I'll just hang out on both.