No factor surpasses the importance of keyword relevancy to Web site content in a search engine such as Google. Although the number of links from other high ranking Web pages to your Web site is very important so to is the content of your Web pages and how it relates to carefully chosen and repeated keywords within the content. These two systems work in conjunction. Content needs to be laid out only after the selection of keywords is determined with very careful thought. A variety of the most specific yet meaningful keywords to base the content of the Web site around is the most important aspect to being recognized as a powerful Web resource. It is a measure of precision. Generalized information is far less useful to anyone than specialized information. Each keyword should have sufficient relevant content, and the keyword should be repeated within the pertinent content itself. The term coined for this is "keyword saturation". The rate at which a keyword appears within the overall content within a Web page is calculated by dividing the total words by the total occurrences of the keyword.

For example: if a Web page contains 1000 words and there are 50 occurrences of a given keyword or phrase, then your keyword saturation on that term is: 50 divided by 1000 = 0.05 (5%)

A good saturation level is 5-7% for Google, but this level varies as search engines keep the internal algorithms and data off which they run secretive in order to deter spam and to maintain the quality of the Web. Keyword saturation is only one aspect of page rank.

One of the most popular free keyword location tools is the Yahoo Search Marketing Keyword Selector Tool. Type in a single keyword and you'll be presented with the number of searches on that term in recent times. More importantly you'll see other popular variations and extensions on that term. http://inventory.overture.com/d/searchinventory/suggestion/

Directly submit the criteria below via Google to obtain the information that follows, or click on the links at the bottom of the search results after submitting a search request for: www.your-domain.com

• Show Google's cache of www.your-domain.com
  (contains information on last crawl date/time)
• Find web pages that are similar to www.your-domain.com
• Find web pages that link to www.your-domain.com
• Find web pages from the site www.your-domain.com
• Find web pages that contain the term www.your-domain.com

The above information can be retrieved by submitting the following search criteria, respectively:
cache:www.your-domain.com/
related:www.your-domain.com/
link:www.your-domain.com/
site:www.your-domain.com/
"www.your-domain.com"

You can view Google's real-time aggregation of keywords based on Web page content (compare to expected keywords) https://www.google.com/accounts/ServiceLogin?service=sitemaps

This is a free service that requires signing up, and it is a great tool for observing Google's acquired information on a Web site. A sitemap can be created easily in XML format using a text editor or a free generator, but it is not necessary. A sitemap contains a list of all pages belonging to a particular Web site including last modified and priority information. It will not increase PR. Instead, sitemaps may assist the spider in locating Web pages more easily for crawling.