Usually we tend to organize the sitemaps.xml files in a human way (by categories).
But for Stackoverflow, due to the number of modifications in each categories, all the sitemaps files would need to be regenerated and they would also be downloaded all the time by the search engines.
So do you know how is the sitemap index file of Stackoverflow organized? Is it organized like a "change log" of only new URLs since last sitemap.xml generation?
<?xml version="1.0" encoding="UTF-8"?> <sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"> <sitemap> <loc>http://meta.stackoverflow.com/sitemaps/2010_02_05.xml.gz</loc> <lastmod>2010-02-05</lastmod> </sitemap> <sitemap> <loc>http://meta.stackoverflow.com/sitemaps/2010_02_04.xml.gz</loc> <lastmod>2010-02-04</lastmod> </sitemap> ... </sitemapindex>
This means that:
- Content update notification is only a matter of "changefreq" and "priority" in previous sitemaps.
- Content deletion is only a matter of HTTP 404?