1. A query builder operated by at least one processing unit for supporting query building processes, said query builder comprising: 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 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.