Q2A is being updated regularly and its good.
I don't think by using particular platform it will boost your website traffic. You must concern with your content and site niche you have passion about.
You can have the best platform and tools in the world but without good SEO and marketing skill, i think your site will not go anywhere. + good niche u're interested in!
My friend and I build 2 different blogs, we both use Wordpress platform, the same wp theme, the same plugins, the same niche! but he doesnt have the passion like I have. He just after the money.
1.5 year later, my blog brings 60,000 visitors aday while his blog still only 500 visitor aday!
How is that happen? u can guess
Im using Q2A for a week now, and i pretty much lovin it.