httpwebwitch - 8:55 pm on Jul 3, 2012 (gmt 0)

Can an XML sitemap automatically detect new web pages

Not without help. a simple XML file isn't going to change itself. But there are server-side scripts and tools you can use to "refresh" your sitemap with new content.

Popular options include XML sitemap plugins for WordPress (and other CMS's), and PHP-based solutions that crawl a site to generate a new XML file.

How exactly does an XML sitemap communicate with the website/CMS?

If you're using a CMS, then your sitemap.xml file might be dynamically generated. In which case, adding a new page to the CMS adds it to the sitemap at the same time. A CMS that doesn't do that would be rather poor

Submitting URLs to Webmaster Tools

submit to webmaster tools, add it to sitemap.xml; those are two ways to tell Google that your URL exists. A third is to create a link to that page, then wait until the Googlebot crawls your site and follows the link.

hosting a sitemap makes it easier for the bot to find URLs