So does a properly constructed menu system. Spiders only periodically crawl the XML sitemaps, just like they only periodically crawl the robots.txt file. They should be able to find new pages in your site every time they visit the site through the menu system.
Originally Posted by stuartmike4
Once again, the purpose for an XML sitemap is to help spiders find obscure pages that have become buried over time. It is not intended to help spiders find new pages. Read the Google article about XML sitemaps.
Many spiders will only crawl pages within 3 or 4 clicks from the home page. That is how pages get lost over time. The XML sitemap keeps those pages visible to spiders. That is why it doesn't do anything for a small site.
Normally there are two types of sitemaps. Sitemaps.xml and sitemap.html. They both are very important. One is for search engine spiders while others are for users. You have to add both for your website.
There is two type of site map ,but XML site map is more effective.
A sitemap gives the spider a rapid guide to the structure of your site and what has changed since last time. If your website is having indexation problems, has a poor internal link structure, or falls in one of the three situations described by Google, then using a Sitemap would probably be a good idea.