The invention relates to a method and a system for determining a profile of a communications network user, the method includes:
saving profile data regarding known network users in a database, these users forming a reference population, the profile data (Pi) regarding known users including a set of attributes (j) values (Pij) associated to each user (i),
for each site or part of site (s) of a set of sites of interest accessible via the network, processing a set of probabilities (Psj) that represent the attribute values of users that connect to the site or part of a site (s), according to the connection history of the users of the reference population to a site or a part of a site, and processing a probability that a user to be identified has a given attribute, according to the probabilities associated to the Internet sites or parts of a site (s) of interest to which the user connects during a specific time period.
The method is characterized in that the processing determines the probability (m3j) that the user to be identified has a specific attribute (j) as a combination of a decorrelated probability value (m1j) that takes into account the probabilities associated to the Internet sites or parts of a site (s) and a correlated probability value (m2j) that takes into account average profile data (gj) regarding the users that are part of the reference population.