University of Maryland University College
In the ever-growing World Wide Web (or the web, for brevity, hereafter), search engines are indispensable facilities enabling individuals to find web pages of interest efficiently. However, as estimated in 2000, 550 billion web pages were not reachable by search engines. Compared with 8.41 billion web pages collected and indexed by search engines as recorded in mid-March 2012, only a very small fraction of web pages are really searchable. Even worse, those unsearchable web pages should have been blooming along with the growth of the entire web over the past decade.