Big three search engines to use common indexing tool
 

Google, Microsoft, and Yahoo will all begin using Google Sitemaps in an attempt to standardize and improve the website indexing process. Sitemaps are XML files describing the layout of the site with associated metadata. Those files can let web spiders know the last time a page changed and how important a changed page is so that the indexing process is streamlined. With sitemaps, only pages with changes are visited, which saves bandwidth.