1. A method for automatically searching at least one information source ( 2 , 3 ) accessible through a data network ( 6 ) for contents ( 4 A- 4 F) that are supplied by this information source ( 2 , 3 ) and satisfy at least one predefined criterion, which contents comprise useful information (NI) and metadata (ZI) that characterizes the useful information (NI), the information source ( 2 , 3 ) changing the content supplied by it under the control of control signals (CTRL), comprising: selecting an information source ( 2 , 3 ), receiving at least a part of the content ( 4 A- 4 F) supplied by the information source ( 2 , 3 ) selected, which part contains the metadata (ZI), analyzing the metadata (ZI) in respect of the predefined criteria and, if the criteria are satisfied, processing the useful information (NI) received, and for as long as the at least one predefined criterion is not satisfied, generating a control signal (CTRL) and transmitting it to the information source ( 2 , 3 ) to change the content ( 4 A- 4 F) supplied by the information source ( 2 , 3 ), and again receiving at least a part of the content ( 4 A- 4 F) supplied by the information source, which part contains the metadata (ZI), and analyzing the metadata (ZI) in respect of the predefined criteria.