Importance of the search service in a site

It is also required to mount the function of the search in a site and to raise the accuracy with to perform the navigation design after layered-structure-izing for every category of information as a method of raising the information retrieval nature in a website, and displaying the link to the suitable pertinent information according to the contents of each information contents.
At a site especially with much amount of information, although a user is found [ one's information needed ] specially, while following 1 page of pages at a time, arriving at the information on target becomes difficult.
It could be said that the function of the search in a site is indispensable, when its thing needed is already decided at EC site etc.

U.S. WebSideStory saw the news of "having released the results of an investigation that it was necessary to raise the accuracy of the search in a site in order to raise the navigation of a site."
It is 4 percent of higher ranks of the search query in a site, and it is the reason to form 50 percent of all search.
When it limited to especially EC site, the result of forming 50 percent of the total number of search was also obtained only by the search query of 2 percent of higher ranks.
INTERNET Watch: Results of an investigation that 50 percent of all search by the query of 4 percent of higher ranks of the search in a site is occupied

It also seems that "the person using the search in a site is connected with purchase by the probability of being 3 times much as an average visitor" is said in this report.
It is enabling it to acquire information needed, without offering the search service in a site with high accuracy which can arrive at its information needed in an instant to the user who visited the site with the purpose clearly also at an aiming at sale company site unlike the conventional navigation experience, and a user feeling stress. Is aiming at improvement in user experience important?