Optimizing query processing for the hidden web

The term Deep Web (sometimes also called Hidden Web) refers to the data content that is created dynamically as the result of a specific search on the Web. In this respect, such content resides outside web pages, and is only accessible through interaction with the web site - typically via HTML forms. It is believed that the size of the Deep Web is several orders of magnitude larger than that of the so-called Surface Web, i.e., the web that is accessible and indexable by search engines