This is a preview feature within the new CFMBB forum that shows the contents of thread before it is clicked on or viewed.
With this feature, when you hover your mouse over a forum thread post, the post's title and message/content will be visable
1. Go into your site and into the new CFMBB forum, choose the forum/thread where you wish to place your reply within:
2. Within the selected forum as you view forum threads you can hover your mouse over thread titles and a preview box will appear. This box shows both the forum title and the forum message/content: