While it has become second nature to webmasters and designers to include sitemaps in their site files, many amateur site builders or site owners who lack a useful webmaster don’t necessarily know how important a sitemap is.
XML Sitemaps are a protocol allowing site owners to inform the search engines about the pages on their website. In addition to listing the pages that you would like the search engines to know about you can also specify some additional information such as the time a page was last updated, its importance relative to the rest of the site and how often the page is expected to change.
Accessible via the Google Webmaster Tools, you can tell Google that something has changed simply by prompting Google to re-download your sitemap. Even if you don’t perform the prompt, Google (and other search engines we pretend to care about) will download the sitemap every time they re-index your site.
Why do we care about Google knowing we have updated a page?
Well, one of the most important ranking factors in the Google algorythm is how fresh your content is. A site that has frequent updates to content is considered a trustworthy site that someone is taking care of. In a world where content is king, it is crucial to let the search engines see update is changing as soon as possible.
While using a sitemap does not guarantee that the search engines will index all pages of a site, they provide better information for the search engines to make use of when they do come visit.
And now for the best part of all… Making a sitemap is easy thanks to automated sitemap generators like the one here: