There is a certain chasidic group which conducts siyumim on the radio during the nine days [as opposed to other chasidic groups who don't know what a radio is and יהא חלקי עמהם - my lot should be among them] after which many people eat meat. I have not seen any sefer that discusses whether listening to a siyum on the radio is enough to allow one to partake of meat but I can imagine that many would argue that if one is not present - it doesn't count.
If anyone sees anything about it please enlighten me....
PS - I am enlightened! I saw on the Yeshivat Beit El website that the former Sefardic Chief Rabbi, Harav Mordechai Eliyahu ztz"l, ruled that the radio siyum doesn't fly. Milchig it is....