This is a site that is a copy of a dynamic web site or a group of web pages from a dynamic site, that is saved as static HTML files. It actually mirrors or acts as a duplicate site. A mirror site is an exact duplicate of another site. From an SEO point of view, having mirrored sites can trip duplicate content filters from the search engines. As a result the search engines may impose a penality on one or all of the sites that participate in the mirror process. The worst case scenario is that the search engine removes the site (and all of its subsequent rankings) from their index. Site owners have used mirrored sites as a method to allow faster downloads for users at a specific geographical location. As an example, a U.S. server could be mirrored in Canada allowing Canadian Internet users to download content faster from the local Canadian server than from the original American one. Mirrored sites have also been used for load balancing and to preserve historic content.