Duct Tape Marketing has a couple of posts around having a search tool on your site.

This is yet another area where the marketing and usability worlds collide.  As I posted in the comments on DuctTapeMarketing:

While adding an on-site search engine would seem to be a no-brainer, it can actually cause the users of your site to fail more often than if you *didn’t* have one.

Strange, I know, but Search is a site feature that looks simple on the surface, but grows in complexity as you begin to peel the layers off.

Before implementing on on-site search engine, I’d suggest perusing the search-related articles by User Interface Engineering:
http://www.uie.com/browse/search/

The research available around the use of search has convinced me that for some small business sites it’s more trouble than it’s worth.

The main reason I have a search tool here on Boyink.com is for my own benefit.  I often remember blogging about something I want to revisit or send to a client so use the search to find that archived post.

And here’s a small “meant in a good-natured way” chuckle—try to find a site search on the article I linked to at DuctTapeMarketing.com.