Here is another theme that turns your WordPress website into a dynamic questions and answers community. Scisco lets your visitors ask questions and grow their reputation by answering them. It supports private messaging. Your community members can like and dislike answers and follow others.
Scisco is not only a Q&A theme but also a job board. It works with WooCommerce too, so you can fully monetize your site with your own merchandise and products. This theme lets your members select the best answer for their questions. Inappropriate posts can be flagged for community moderation. Scisco also supports private questions.