1. A computer-implemented method for using a computer to regulate a user's access to a Web page, said method comprising the steps of: hashing a URL associated with a Web page requested by the user, wherein the hashing comprises separating the URL into a plurality of pieces and hashing each of the pieces separately to form a plurality of hashed URL pieces; receiving a list of one or more categories responsive to the plurality of hashed URL pieces; comparing categories in the received list with categories in a pre-stored list; and regulating access to the requested Web page based upon results of the comparing step.