By default, if you have a site map activated on your site, all new pages that you add to your Web site will be automatically added to your site map pages. However, sometimes you may not want to include a particular page on the site.
A few examples of pages you may not wish to include on the site map are:
Thank you page – If you have a thank you page that people arrive at after placing an order you are unlikely to want to include it on the site map as neither a search engine spider or a human viewing the page are likely to find it useful.
Legal Disclaimers – It is common practice to include legal disclaimers on a menu at the foot of the main body or the foot of the page. Including them on a site map is not really necessary as they are not the kind of pages that you are going out of your way to promote. If people want to read your terms and conditions, and other such legal documents, you should make them easy to find by putting them on their own link at the foot of the page instead.
Pages that are out-of-date – This is a matter of personal choice and will very much depend on the kind of page and the kind of site you are running. Often it is prudent to leave old pages on the site, simply because people may click on a link from another site that takes them to that page.
You wouldn't want them to see a ‘page not found error’ because you had deleted that page so instead you leave it on the server just in case (please note – you can of course add an appropriate message at the top of that page to let people know they've reached an old page and you may wish to include a link directly to the new page). However, just because you've left the old page on your site does not mean you want people to find it via your site map pages.