Note: The images in the following screen shots say "Community Server" instead of "CFAITH Communities" and may have different colors. However, the procedure is exactly the same.
The CFAITH Communities site allows you to find forum posts by a certain member by using a menu button item, as shown below. Clicking on the "Contact" menu button within a forum post will display a "Find posts by [user name]" menu item.
Clicking on this menu item will display a list of Blog, Forum, and Gallery posts by the member who posted the original message.