Rollover bandwidth

1

i actually can’t understand this “rollover bandwidth” correctly. i know when someone visits a website, the number of bytes used gets added up to the bandwidth, so the bandwidth used number goes up, and if that goes over the limit, the owner of the website has to pay more. cool! let’s say if it is media-temple, how do they actually determine how much one visitor will use number of bytes? i know using bytes depends on the time one spends at a certain webpage. so does it also depend on the size of that webpage or what? thanks for you reply…