Google Page Creator

If you have a site hosted by Google Page Creator, be prepared for a surprise. Google automatically builds a sitemap file that lists each and every file from your site created or only hosted by Page Creator.

The address of the sitemap file is http://sitename.googlepages.com/sitemap.xml, so anyone who knows the URL of your site (or just your Gmail address) can find all the files from your site. Some sitemaps are even included in Google search.

That means you shouldn't use Page Creator to upload personal files because even if you don't link to them, their addresses are easy to find in the sitemap. But there's also a bright side: you don't have to build a sitemap for your site to submit it to Google Webmasters Central.

http://googlesystem.blogspot.com/2007/04/google-page-creators-sitemap.html