1. A method for creating sketches of sets to permit comparing set members selected from a universe U with a size w, comprising: selecting a size k for a sketch N; providing a randomizer; providing set S as a subset of U; processing the set S by the randomizer to provide vector P; normalize vector P to provide a number s; determining sketch N by dividing each element of P by s; sketch N when compared with at least one sketch N′ permitting a user to compare a degree of similarity between the members of set S to at least one set S′.