26. A system for detecting unwanted conversational media sessions, said system comprising: a reference database, stored in a non-transitory computer readable storage media and including one or more reference data items, each reference data item including data in respect of a packet arrival times associated with a previous conversational media session; and a packet arrival similarity evaluation module, stored in a non-transitory computer readable storage media and configured to be executed on a computer processor, said evaluation module adapted to obtain data in respect of packet arrival times associated with a real-time conversational media session, and being further adapted to evaluate similarity between the data in respect of the packet arrival times associated with the real-time conversational media session and packet arrival times associated with a reference data item taken from a previous conversational media session, and output an evaluation result; and a determining module, stored in a non-transitory computer readable storage media and configured to be executed on a computer processor, said determining module adapted to determine, based on the evaluation result, whether the real-time conversational media session is wanted or unwanted.
49. The system according to claim 26 , wherein said packet arrival similarity evaluation module is adapted to calculate two or more progressive similarity scores each with respect to a different instant during the progress of the real-time conversational media session, wherein each of said scores corresponds to the similarity between the packet arrival times associated with the real-time conversational media session which were available at the corresponding instant and the reference data, and said evaluation module is adapted to evaluate progressive similarity between the real-time conversational media session data and the reference data based upon the two or more progressive similarity scores.