... 
"Even if users can't find what they're looking for through well-labeled links, many companies offer site searching as a shortcut to information. But the study found that site searching was not only useless but also detrimental for information gathering: users were 50 percent more likely to find what they were looking for if they never hit the search button." 

From Web shocker: How a $10,000 site beat a $300 million site. CNet's News.com, 16th April 1998