The second best forum host the Zathyus Network has created, it is founded in September 2002 by Brandon Kopetzky. It is often shortened to IF. According to its terms of service, InvisionFree does not restrict forums on the basis of post, topic, or member number, nor bandwidth, nor will forums be deleted for inactivity. Google AdSense is the site’s main source of revenue; however, users may pay InvisionFree to remove ads from their site, or to make more space available for file uploads. InvisionFree boards are subject to several limitations, though; among them are the inability of the administrator to access the MySQL database directly or to access the board's filesystem via FTP. If you know advanced HTML, you can create custom skins for your forum. You can convert from Zetaboards if you haven't already.
Invisionfree is an awesome forum software, but I recommend you convert to Zetaboards.