Sitemaps allow you to inform search engines about pages on your website that are available for crawling. A sitemap is an XML file that lists URLs within your site, as well as additional information about each URL such as when it was last updated, how often its content changes and its priority within the site. The purpose of this is to help search engines to more intelligently crawl your website, with the ultimate aim of improving your SEO and pagerank.
Note that this add-on creates XML sitemaps and not HTML sitemaps, for your front-end site. Find out more about sitemaps at sitemaps.org.
The Sitemap Module allows you to select which channels to include in the sitemap and to set preferences for each channel - its url structure, change frequency and priority. You can also add individual URLs to the sitemap and set their preferences.
For each channel that you include in the sitemap a Sitemap tab will appear when publishing or editing an entry, allowing you to select whether or not to notify seach engines that your content has changed. The checkbox is checked by default only when publishing a new entry. The search engines that are currently supported are Google, Bing and Ask. Yahoo recently removed its sitemap ping service so has been removed from the add-on.
Reviews taken from devot-ee