A method for automatically searching at least one information source accessible through a data network for contents that satisfy predefined criteria, which contents comprise useful information, such as stream of audio, video or news data, and metadata that characterizes the useful information, comprises: selecting an information source and receiving the metadata and analyzing it in respect of the predefined criteria. If the criteria are satisfied, the method includes processing the useful information received. If not, then for as long as the predefined criteria are not satisfied, generating a control signal and transmitting it to the information source to change the content supplied by the latter, and again receiving the metadata for the content supplied, and analyzing the metadata in respect of the predefined criteria.