Is P2P dying or just hiding?, authored by Thomas Karagiannis, Andre Broido, Nevil Brownlee, kc claffy and Michalis Faloutsos:
Recent reports in the popular media suggest a significant decrease in peer-to-peer (P2P) file-sharing traffic, attributed to the public’s response to legal threats. Have we reached the end of the P2P revolution? In pursuit of legitimate data to verify this hypothesis, we embark on a more accurate measurement effort of P2P traffic at the link level. In contrast to previous efforts we introduce two novel elements in our methodology. First, we measure traffic of all known popular P2P protocols. Second, we go beyond the “known port” limitation by reverse engineering the protocols and identifying characteristic strings in the payload. We find that, if measured accurately, P2P traffic has never declined; indeed we have never seen the proportion of p2p traffic decrease over time (any change is an increase) in any of our data sources.