1. An apparatus for generating a navigation map, the apparatus comprising: a memory; and at least one hardware device, coupled to the memory, operative to: for a given web site visited by a user, store in a node for said given web site an address for said given web site, a relevance rating for said given visited web site indicating an importance of said given visited web site to a web navigation task of said user, and a link from said given visited web site to a next web site visited by said user; generate a navigation map comprised of said nodes for a plurality of said visited web sites, wherein each node in said navigation map corresponds to a given one of said given web sites visited by said user and is connected by an edge to at least one other node in said navigation map, wherein a presentation of at least one node in said navigation map is based on said relevance rating; merge a plurality of said navigation maps for a plurality of users, wherein each of said plurality of said navigation maps is comprised only of said nodes for said plurality of said visited web sites visited by said respective user, wherein each node in each of said navigation maps is connected by an edge to at least one other node in said respective navigation map, wherein said plurality of said navigation maps are merged from a common point by identifying nodes in said plurality of navigation maps corresponding to a same web page; and determine a relevance rating for a given node in said merged navigation map based on one or more conflict resolution rules that process a plurality of relevance ratings indicating whether or not said given visited web site associated with said given node is important to a web navigation task of said respective user to resolve conflicting relevance ratings of said given node by different users in said plurality of navigation maps, wherein said one or more conflict resolution rules determine a merged relevance rating for said given node that aggregates a plurality of said users marking said given node as relevant and a plurality of said users marking said given node as irrelevant, wherein said relevance rating of said given node by each user indicates a relevance said importance of said visited web site associated with given node to said web navigation task of said respective user.