SEF Service Map is the only active site map available. Thanks to a built-in PingBack mechanism (http://en.wikipedia.org/wiki/Pingback), the site map can actively report (ping) new or modified items to google.com, yahoo.com and other services. Thanks to that, indexing robots (spiders) will visit your site much more often and the site can index itself without your further activity. Once your site becomes a trusted site for search engines, your new or modified items will be able to appear in the index after a few hours;