This add-on is designed to allow posting of html in your forum. It adds a html button to the Rich Text Editor, which then it will parse the html in posts, threads, signatures, personal conversations and in all the other third party add ons that make use of the the Rich Text Editor such as my Articles Manager add on, or the Resource Manager to name a few.
Only users that are allowed to Use parse html bb code in the permission system, can make use of this option. IMPORTANT: Be very careful as to whom you grant that permission, because allowing everyone to post html can pose a security risk for your forum. You should allow only very trusted persons with this.