Youtube uses enough data per day that it's measured in Petabytes instead of Gigabytes.
Around 24 TB of data is uploaded every single day.
From what I've read on the internet before An estimate of the amount of Data Youtube uses per day is around 100000 Petabytes of data are used in a day between the videos being uploaded, downloaded.
I hear it also cost around 5 million dollars a month to run.