Your website, Yoomoot, isn't that old, but has yet a lot of users and looks quite successful concerning to the amount of content you actually can present.
I want to add: now that I have worked with it for some questions and follow up questions, I find it very comfortable to arrange a discussion - and the generated overview is an eye-candy and easy to use as well.
But I miss one thing: how about adding a quick-comment-function, like we know it from www.stackoverflow.com - there you can add one-line comments under each entry. For your site I would say it won't matter if it is a question or an answer, everybody should be able to put a comment under the text fields.
We got two articles published in techcrunch.com which have had by far the biggest impact in growing Yoomoot.
Other than it's just been a steady trickle from people discovering our Twitter profiles (mainly though us following people who might be interested in us).
As for allowing quick-comments, see this question