Patent ID: 8156218

Claim:
A computer-implemented method for tracking a cumulative number of unique visitors to different objects and an order of visiting said different objects, each of which may be visited by multiple visitors, said method comprising: maintaining a data structure that contains records relating to each of said objects and to each combination of two or more of said objects, the data structure further contains records relating to each of said objects and to each permutation of said objects, wherein said objects are different websites displaying the same set of advertisements of the same campaign; for each visitor visiting an object (S M ) for the first time: determining, using a website overlap code, a current combination of objects previously visited by said visitor; if no objects have been previously visited by said visitor: if the data structure contains a record relating to said object (S M ), incrementing said record relating to said object (S M ); if the data structure does not contain a record relating to said object (S M ), creating a record relating to said object (S M ) and setting said record to 1; if objects have been visited by said visitor, decrementing the record relating to said current combination of objects and: if the data structure contains a record relating to the combination of said object (S M ) with the current combination of objects, incrementing said record relating to the combination of said object (S M ) with the current combination of objects; if the data structure does not contain a record relating to the combination of said object (S M ) with the current combination, creating a record relating to the combination of said object (S M ) with the current combination and setting said record to 1, wherein the data structure provides an indication as to the cumulative number of unique visits to each object and each combination of objects, thereby providing the indication as to the cumulative number of unique visits to each website and each combination of websites participating in the same campaign; and tracking the order of visiting said different objects based on a permutation of said objects previously visited by a visitor.