There were two interesting articles on site search, searches done directly on a web site versus a web search engine, recently. The first was from Shaun Ryan where he estimated the search volume of site search compared to web search. He shows that web searches are performed about 200 million times per day. But based on his best guesstimation, there are more than 2 billion site search done per day. If that is the case, a new study from Lou Rosenfeld on how site owners view site search might be interesting to read. The study asked four questions and received 134 responses.
The most interesting question was "We're surprised at how few people and organizations analyze their own site's search queries. If you agree, why do you think it's so uncommon?" Top reasons were not having time or not having the right tools.
You can read all the responses at RosenfeldMedia.com, but I don't think you will be surprised by some of the responses.