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The Sitemaps protocol allows a webmaster to inform search engines about URLs on a website that are available for crawling. A Sitemap is an XML file that lists the URLs for a site. It allows webmasters to include additional information about each URL: when it was last updated, how often it changes, and how important it is in relation to other URLs in the site. This allows search engines to crawl the site more intelligently. Sitemaps are a URL inclusion protocol and complement robots.txt, a URL exclusion protocol. Sitemaps are particularly beneficial on websites where: * some areas of the website are not available through the browsable interface * webmasters use rich Ajax, Silverlight, or Flash content that is not normally processed by search engines. * The site is very large and there is a chance for the web crawlers to overlook some of the new or recently updated content * When websites have a huge amount of pages that are isolated or not well linked together, or * When a website has few external links Search Engine Indexing Sitemaps supplement and do not replace the existing crawl-based mechanisms that search engines already use to discover URLs. Using this protocol does not guarantee that web pages will be included in search indexes, nor does it influence the way that pages are ranked in search results. Specific examples are provided below. * Google - Webmaster Support on Sitemaps: "Google doesn't guarantee that we'll crawl or index all of your URLs. However, we use the data in your Sitemap to learn about your site's structure, which will allow us to improve our crawler schedule and do a better job crawling your site in the future. In most cases, webmasters will benefit from Sitemap submission, and in no case will you be penalized for it."〔(【引用サイトリンク】 title=About Google Sitemaps )〕 * Bing - Bing uses the standard sitemaps.org protocol and is very similar to the one mentioned below. * Yahoo - After the search deal commenced between Yahoo! Inc. and Microsoft, Yahoo! Site Explorer has merged with (Bing Webmaster Tools ) == History == Google first introduced (Sitemaps 0.84 ) in June 2005 so web developers could publish lists of links from across their sites. Google, MSN and Yahoo announced (joint support for the Sitemaps protocol ) in November 2006. The schema version was changed to "Sitemap 0.90", but no other changes were made. In April 2007, (Ask.com and IBM announced support ) for Sitemaps. Also, Google, Yahoo, MS announced auto-discovery for sitemaps through robots.txt. In May 2007, the state governments of (Arizona, California, Utah and Virginia ) announced they would use Sitemaps on their web sites. The Sitemaps protocol is based on ideas from "Crawler-friendly Web Servers," with improvements including auto-discovery through robots.txt and the ability to specify the priority and change frequency of pages. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sitemaps」の詳細全文を読む スポンサード リンク
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