I have agree with you, Yahoo! answers could not control what their members are posting on it while Quora is becoming a platform for self promotion and advertising without moderating from their staff.
I've actually seen people come in and post "Well, I'm getting +2 points for this post" and that's it. The moderation of Yahoo answers is a joke
Quora has automated systems that remove people who post too many links. I haven't figured out the ratio yet, because I'm not banned lol
But I post a link in around 1 in 10 posts on there and I've never gotten contacted about my posts.
Most people wanted to do this right way but no more could not. What things in your mind to do it right and getting traffic?
Setting up a Q&A type website would take a lot of time. You would have to post loads of questions on your own and even hire Virtual Assistants in countries like India and the Philippines to post all day every day to get content on there. Eventually your website would get ranked for some questions and begin the snowball affect.
You would have to moderate the posts, or have an auto moderation feature for someone who posts too many links. Otherwise it will turn into a link farm and that's never good