2.8 Fatemeh et al. (2012) [13] declares that Information extraction of the Web and more precise ranking methods of Web pages are the most important issues in search engines, research area due to the ever-growing and dynamic nature of the World Wide Web. These applications should not only provide information about the demand of users with accurate and up-to-date search answer set, but also their ranking strategy of items in answer set are critical due to the limited patience of today’s users. A Web crawler as a part of a search engine traverses the Web graph and fetches any URLs from the initially provided URLs, keeps them in a priority-based queue as crawl frontier and then according to a Web page importance metric selects the first most important URLs for further processing in an iterated manner. The performance of any Web crawler within the architecture of search engines is highly dependent to the applied Web page importance metric. The existed metrics relies on the link structure of Web graph or employs the techniques in order to check the context similarity between each issued query and Web pages.
