Add a Search Engine to Your Site
A search facility on your site is a useful feature where you have more than a few pages.
They can be free for non commercial use and adding the code to your page is easy. Usually they are supported by advertising as is this one here. I preferred this one originally as the advertising was more discreet than others but when I looked in June 2005, there wasn't much difference.
Another useful features is statistics. As I write this first time, there are absolutely no statistics for this site -- I have done a few test searches only. These tell you what search terms your visitors are using, and should allow you to over time to improve your site to cater for their tastes.
The search index lives off site, on the site of the Search Engine provider, When your visitor fills out the search form, your page builds the query and sends it to to that site. The search results come back from there.