Abstract: A method, a device and a system are proposed for controlling advertising in an information network, in particular the Worldwide Web (WWW), via which several users have access to information. The system has a data-processing device formed as a profiler which allocates a user identity to every user and which evaluates first data which a first device provides and which contains details about his access behaviour to the information, in particular logfile data. The profiler also evaluates for the respective users second data which a second device provides and which contains details about the users' interests in the type of information which is preferably gathered via questionnaires online and/or offline. The profiler supplements the first and/or second data with third data which a third device provides and which contains details about the identity of the respective user. These personal data come from a service provider system such as e.g. the freemail system www.freemail.de.