According to Sandvine 2007 Internet report, BitTorrent is 52% of upstream and 10% of downstream traffic (in North America). At the time this put it behind Netfl

According to Sandvine 2007 Internet report, BitTorrent is 52% of upstream and 10% of downstream traffic (in North America). At the time this put it behind Netflix (24% total) but on a par with HTTP (17% total for both) for aggregated net usage. Whilst I wouldn't argue that all BitTorrent traffic is pirated I wouldn't argue all HTTP traffic isn't either. Somewhere around 17% of internet traffic being used to pirate does seem a reasonable estimate though. 17% is far from being most internet traffic but is indeed a very noticeable amount, which would indeed have an affect on the experience of legitimate users. This idea that piracy is detrimental to the internet experience for other users is one I find interesting and haven't heard mentioned before.