The search engines see a link like http://mysite.com/ as a different page than http://mysite.com/index.php or http://www.mysite.com. Since all three links will point to the same page, they may perceive this as an attempt to fool them. They call this "Duplicate Content" and may ban a page, or even a site, for it. You can tell if your site is using both links by clicking in your logo, if it is clickable, or in the home page link in the breadcrumb. Doing that in a standard oscommerce shop will cause the url to change so that it contains index.php. This change will alter the basic code so that only one of the links will be a direct link. The others will be redirected to that main link, thus preventing the possibility of a duplicate content situation. We will also change the logo, breadcrumb and footer code for links that may use it.