2. The method of claim 1 , wherein analyzing the stored sitemap information to identify a respective website having sitemap information that is at least potentially out of date comprises analyzing the stored sitemap information to identify a respective website having sitemap information that is older than a shortest predicted update period for at least one document listed in the sitemap information for the respective website.
2. The method of claim 1 , wherein analyzing the stored sitemap information to identify a respective website having sitemap information that is at least potentially out of date comprises analyzing the stored sitemap information to identify a respective website having sitemap information that is older than a shortest predicted update period for at least one document listed in the sitemap information for the respective website. 3. The method of claim 2 , wherein analyzing the stored sitemap information to identify a respective website having sitemap information that is at least potentially out of date comprises subtracting a last modification date in the sitemap from a current date.