Many web site owners seem to believe they should only put what they think to be important pages on an xml site map, instead of all of the pages that should be indexed. Sometimes, they put absolutely everything that they have on the xml site map, like zips and PDFS and text files that are duplicates of web pages.People who misuse sitemaps, intentionally or unintentionally can suffer from this technology. In fact, it makes it hard to see what the point of sitemaps actually is.