Do you have a 'search' box on your website? If so, you have a great opportunity to get inside the minds of your visitors. You can "listen" to their thinking as they go through your site.
What people search to get to your website (in Google, MSN, Yahoo) and what they search when they are on your website are vastly different.

Note how the results for external searches are broader categories. The searches for items inside your site are much more specific. They are looking for a specific resource on your website.
Here are 6 reasons why you need to pay attention to internal searches:
1. Know Your User
Seeing what people are searching while they are on your website gives you clues into how your user thinks, what they are looking for, and even what they perceive your website can offer them. This anecdotal information is critical for learning who your audience is so you can best serve them.
2. Navigation Gaps
This feature can reveal gaps in your navigation structure. Your users will often try to find what they are looking for by using normal navigation. When that fails, they will resort to the internal search. If you see words repeated often--especially words tied to a specific product or resource that you offer, this is a clue that you need to:
3. Hints for Common Misspellings
You can find specific misspellings that people make for your resources. Those misspellings can then be incorporated into your Search Engine Optimization campaigns and Pay Per Click (PPC) campaigns.
4. Customize Your Search Results
Knowing what people are searching for can allow you to display specific products or services that meet their needs. One organization had a high number of internal searches for the term "modesty." We set up a system that would automatically display products tied to "modesty" at the top of the page--before the standard search results were displayed.
5. Find Gaps in your Search Results
It is a good practice to view the actual results your end users see for the words they enter. If your end users are seeing articles and products that don't connect with their search terms, you may need to tweak your search engine to provide more relevent results.
6. Assist in Purchasing Keywords
Site Search can give you hints for other words to include in your Pay Per Click advertising campaigns.

This is useful for all of the reasons stated previously.
Other useful information that Google provides:
There is a wealth of other information available from the Site Search, but the items mentioned will give you a great start in listening to your users.
For starters, there are several assumptions:
Once these are in place, simply log into Google Analytics and view your site reports. You'll see a new option in the menu:

Now you just need to walk through the steps found in the Google Helps and you should be all set.
Happy "listening" to your users. If you have other creative ways you've used the Site Search results, let us know!