Helping Google with sitemaps
A sitemap is just that—a map. It outlines the structure of your website and includes pertinent information such as the date on which it was last updated and the frequency with which it is updated. Suppose that you added an important product to the bottom of a big subcategory. In all likelihood, Google will have to crawl through your entire site to find it and add it to the search results.
With sitemaps, Google can be made aware of this page, any other such pages, and any modifications. Google can then specifically crawl the new or updated pages. This is better for you and easier for Google.
