Ok I do a few things about ISPs, here goes. Usually, NO, they do not have the time or resources to monitor EVERY user, that would be ridiculous. However, yes bandwidth usage is logged and through special software they take the average bandwidth usage and will look for unusually high activity - For example, when the average monthly usage is usually below 20GB and they notice that a group of subscribers are doing 100GB+ on a repetitive basis, it will be flagged and they may, at their discretion look into it - Remember that when you sign up for home internet, you agree that the service is unlimited but based on intermittent use, non commercial use and non abusive. SOme ISPs are more tolerant that others, some will usually warn you if you exceed 100GB - What you should be very careful especially is your UPLOAD bandwidth - if it is that high then you are running a server and sharing files, this also raises a flag. The other thing you should watch for is complaints - When complaints about your accounts are made to your ISp, they do take it very seriously and will act upon it. No, ISPs are not there to monitor and NO they do not monitor WHAT you are downloading - They DO have software and CAN monitor your ports, to see if you are running any server (usually they monitor port 21, 80, etc.) but otherwise they flag abusive downloaders/uploaders. I'd say if you exceed 100Gb (maybe 60GB to be safe) on a monthly basis, then you should try not to make it a HABIT every month. Some ISPs will not bother flagging bandwidth abusers - but if they DO call or send you a letter, they will usually request that you reduce your activity, by law, you they CANNOT ask you WHAT you are downloading or what you are doing, they CAN ask you to tone down your abusive activity but unless they have a warrant they cannot bother you about what you are doing - They can bloody care less what you are downloading just as long as they don't get complaints.