the following is the info on wordtracker.
WordTracker can tell you exactly which terms your customers are using to find the products or services you offer when they use search engines. These are often terms or combinations of terms you may never have considered.
It's very easy to use. Just enter terms related to your Web site, and WordTracker tells you how often people search for those terms. Plus, it also tells you the popularity of related terms, and it tells you how many competing sites use those terms.
As a sample of what it can do, each week WordTracker provides the top 500 frequently-searched words on the Internet. These are taken from various metacrawlers and search engine voyeurs across the Internet and stored in a database of over 300 million search terms.