Like in my attempts to size other markets, it turned out to be hard to gauge just how big the top video sites are globally. None of them publish the same metrics, and the analyst firms often only cite North American numbers. Taking matters into my own hands, I combined Sandvine’s interesting peak bandwidth consumption numbers (the basis for many articles about the growth of Netflix) with Cisco’s annual Visual Network Index, which forecasts the overall bandwidth consumption in each geographical region. Some surprising results:

• Youtube is #1, consuming 7,875 petabytes of bandwidth a month – this is no surprise given a 10 to 1 lead in active monthly users over any other site.
• Netflix is #2 at 6,103 petabytes a month – this is surprisingly close, and shows Netflix’s impressive growth, as well as the effect of full length HD shows and movies.
• Bittorrent is #3 at 3,862 petabytes a month – Bittorrent use has been dropping over time, and while some of this still impressive number is video (some say as high as 85%), it includes all types of content being transferred.
• iTunes is a distant #4 at 817 petabytes a month – this is all downloads, and includes other media. This is an interesting data point reflecting the limits of the rent/buy model versus a subscription streaming service.
• Dailymotion is #5 at 489 petabytes a month. This has some heavy extrapolation since Sandvine only lists the top ten vendors in each geography, but I think it’s fair given Dailymotion’s still large monthly active user base. I will attempt to validate this number further.
• Amazon Prime Instant Video and Hulu should be in the top ten, but one needs to remember that they are not yet available broadly around the world.