Seems to me that there is an abundance of useful content contained within a forum that
nobody reads.
1. Start articles.talkfreelance.com or similar on Wordpress/SEO friendly CMS
2. Edit/rehash the best articles
3. Gradually release them
4. Watch search engine traffic rise
5. Ensure comments are open to the public, but invite guests to 'discuss' in the forum
Just throw an author section at the bottom of each article and you will keep the writers happy.
Additionally, something that always grabs attention is 'trophies'. We need to appeal to people's ego. If someone writes an article, they receive an icon in their profile. If someone sells 10 templates, they receive an icon. 100/500/1000 posts etc. the list goes on.
Displaying these icons publicly will encourage others to join and achieve the same landmarks.
As an example, see this page (not my profile)
http://themeforest.net/user/Shegy - specifically on the top right corner, the user has achievements detailed by icons.