I would like to know that if a website advertises a streaming download as say 100MB, would my download to my computer be 100MB ? Would there be streaming control packets that a service provider would charge for over and above the 100MB content ? Assume the latest RealPlayer viewer. The rub for me is that I have downloaded MIT lectures and according to my file manager the file sizes have matched up to the download sizes on YouTube. However my ISP seems to think that the streams were larger and charged me for more than the file size of the download. I am left wondering where the data came from.