1. A method for improving an implementation of a search engine, comprising: identifying a level of search expertise of a searcher that is using the search engine based on a query behavior of the searcher; identifying the search expertise level based on a post-query browsing behavior of the searcher in relation to a search trail, the post-query browsing behavior defined as browsing behavior of the searcher after a query has been submitted to the search engine and the search results have been returned to the searcher and the search trail defined as a consecutive series of Web pages that lay on a hyperlink trail originating with a click on a search engine result and ending with the searcher performing an activity unrelated to a current search; statistically correlating at least one of a plurality of query behavior features with the search expertise level of the searcher; identifying if and how the searcher uses advanced query syntax and advanced query operators as a query behavior feature such that searchers that use advanced query syntax and advanced query operators are more likely to be identified as expert searchers; and classifying the searcher as either a skilled searcher or a novice searcher based whether the search expertise level of the searcher falls on a continuum of search expertise closer to a skilled searcher or a novice searcher, where the search expertise continuum has at one extreme the skilled searcher and at another extreme the novice searcher; using the search expertise level classification to improve the experience that the searcher has with the search engine when performing a search.
10. The method of claim 1 , further comprising identifying the searcher as a skilled searcher; displaying a higher number of search results per page than normally displayed; displaying a more advanced search user interface automatically without a need for the searcher to click on an “advanced search” button; and displaying detailed information about how and why each search result received it ranking in the search results list.