1. A system for supporting query building processes said system comprising: at least one database including browsing and indexing information relating to visited web pages; at least one processing unit of at least one server, said processing unit comprising: (i) a categorization module, which allows constructing a categorization scenario, which is a logic tree of search categories, wherein said categorization scenario represents statistical relations between categories, allowing the user to select a category therefrom; and (ii) a query scenario module, which receives a selected category and dynamically builds a query scenario corresponding to said selected category, said query scenario is a logic tree having nodes of search terms structured in a hierarchal manner that represents interrelations between said search term nodes, said interrelations are determined according to said selected category and according to browsing statistics relating to searches done by users, wherein upon selection of a node therefrom a search query is automatically created, said search query comprises all search terms that are interrelated to said selected node according to the hierarchal structure of said query scenario, wherein the search terms in the query scenario are determined by assigning a correlation level to each of said web pages' indexes, each said correlation level defines the correlation between the selected category and the index of each of the web pages indicated in said database, wherein said search terms are associated with web pages having a correlation level that is above a threshold value, and wherein the interrelations between the search terms defining the hierarchal structure of said query scenario are determined according to browsing statistics of the associated web pages.