I have a new site and I am new to sitemaps. thanks to the Free Sitemap Generator I quickly got the hang of things. But my question is, Is a single sitemap for a site enough? What I find I am doing is, generating sitemaps for each of my sections by subcategories ie., Motor section will have subcategories Cars: London, Cars:Sussex; I would then write ads for each of these subcategories 200 of them all in one file with individual links and then generate a sitemap. Am I doing the right thing?