An other interesting service provided by Google is Sitemap. While the format was originally developed by Google it is now basically a standard all major search engines are working on. More information you about Sitemaps you can find on Sitemaps.org.
Creating and maintaining such a sitemap for a blog can be quite time consuming, especially if you are writing posts quite frequently. That is where this wordpress plugin comes into the game. It helps you to create the files sitemap.xml and sitemap.xml.gz. On the adminstration page you can choose between many options and customize the sitemap to your needs.
If you are interested in using sitemaps download the WordPress plugin “Google Sitemap” by Arne Brachold. It does not only inform the search engines about the structure of your website, the changes to the website and how often the different pages and posts should be visited by the crawlers. On http://www.google.com/webmasters/ you can see the crawl status of your pages, where the crawlers run into trouble, etc.