This is the first page any visitor to your installation of the software if they do not specify a specific page or feature within the query string of the url. This page also is the only page in the software that does not produce any dynamic output for the (!MAINBODY!) tag. So use of the (!MAINBODY!) tag within this template is useless. Within the default design we send you there is no (!MAINBODY!) tag within the page template used on the home page. That page template has many modules placed within it though that may produce their own dynamic output.