I have a blog, and I have been considering publishing a sitemap for it, which would include the index page, archives page, and an entry for each individual blog post. Is this ever a bad idea? Is it a good (or useful) idea? I'm particularly interested in the <changefreq> element: I edit posts from time to time, and while that's not a common occurrence, I don't want to set a particularly infrequent change frequency that prevents search engines like Google from indexing the edits. (The sitemaps protocol says that search engines may still crawl the pages more frequently, but has no further details on the matter.)