Sitemap

XML sitemaps serve a very niche purpose in search engine optimization: facilitating indexation. Posting an XML sitemap is kind of like rolling out the red carpet for search engines and giving them a road map of the preferred routes through the site. It’s the site owner’s chance to tell crawlers, “I’d really appreciate it if you’d focus on these URLs in particular.” Whether the engines accept those recommendations of which URLs to crawl depends on the signals the site is sending.

What Are XML Sitemaps?

Simply put, an XML sitemap is a bit of Extensible Markup Language (XML), a standard machine-readable format consumable by search engines and other data-munching programs like feed readers. XML sitemaps convey information about one thing: the URLs that make up a site. Each XML sitemap file follows the same basic form. A one-page site located at www. Example .com would have the following XML sitemap:

The XML version and urlset are the same for every XML sitemap file. For each URL listed, a <url>and <loc> tag are required, with optional <lastmod>, <changefreq> and <priority> tags. The URL information, outlined in red above, indicates the information that changes for each URL. The<loc> tag simply contains the absolute URL or locator for a page. <Lastmod> specifies the file’s last modification date. <Changefreq> indicates the frequency with which a file is changed.<Priority> indicates the file’s importance within the site. Avoid the temptation to set every URL to daily frequency and maximum priority. No multi-page site is structured and maintained this way, so search engines will be more inclined to ignore the whole XML sitemap if the frequency and priority tags do not reflect reality.

The URLs in an XML sitemap can be on the same domain or different subdomains and domains. However, each XML file can only contain 50,000 URLs per file and is limited to 10MB in size. To conserve bandwidth and limit file size, XML sitemaps can be compressed using gzip. When a site contains more than 50,000 URLs or reaches 10MB, multiple XML sitemaps need to be generated and called together from an XML sitemap index file. In the same way an XML sitemap lists URLs in a site, the XML sitemap index lists XML sitemaps for a site. The areas to modify for each XML sitemap listed are outlined below: