The days where Site Maps meant one thing are no longer around. Today when someone is referring to a Site Map it may be an actual page on their website that serves as a guide, it could be a XML file listing all of the website's URLs along with attributes for use with Google Webmaster Tools and the other search engines or it may be someone simply referring to Google Webmaster Tools, which used to be referred to as Google Sitemaps.
Site Maps serve an important role in search engine optimization. First let's discuss a Site Map meaning an actual page on the website. From a visitor's standpoint: A Site Map should serve as a table of contents for your visitors. Prominently place a link to Site Map on all pages, therefore if a visitor does get lost, they can easily find what they are looking for.
From a search engine marketer's view, the Site Map should provide the search engines with an easy route into all your website's pages. By using relevant key phrases in the links off your Site Map you better map out what your site is about for Google, Yahoo, MSN and the other search engines. It serves as a table of contents to the search engines as well.
A Site Map on your website can easily be tailored to your visitors as well as the search engines, providing double the impact. Every website should include a well linked Site Map.
Site Map XML Files
Now, the other Site Map. Many refer to the XML file for a website as a Site Map as well. You think, well how does someone get Site Map out of XML. Easy. Through Google Webmaster Tools as well as the other search engines you can submit your website's XML file. In the past, Google Webmaster Tools was called Google Sitemaps, thus where the confusion began.
The XML file serves the same purpose as the actual webpage Site Map. It is a table of contents for the search engines. Within the XML file you can assign certain attributes to each URL, telling the search engines which URLs are most important to your website. Below is an example of an entry for a URL from a XML file.
Through the XML file you can assign an attribute of daily, weekly, monthly or even yearly for how often a page typically changes with the attribute. The priority is what I touched on earlier. You assign values ranging from 0.1 to 1.0 on how important a page is with 1.0 being most important. Typically you should only assign your website's home page and actual Site Map web page a 1.0. Then the priority should follow your website's architecture down from there. In the end, providing the search engines with yet another outline of your website.
Both the actual Site Map web page as well as the XML file are important pieces of the SEO arena. They provide direct "paths" for the search engines to follow around your website as well as a guide for your visitors.