Unfortunately just calculating carbon footprint accurately is not going to tell us if the internet is good or bad for the climate.

We need to know the opportunity cost. What is the carbon footprint on best foregone option?

If when people sit an hour still in their home playing games, watching movies, surfing the net, what would they substitute it with? If they drive to somewhere, travel more etc. what is the carbon footprint then. Same for work use. If you reduce internet use, do you lose efficiency and increase carbon footprint or not?

Can anyone shed any light on whether these numbers make sense at all? I think 0.2 g of CO2 per minute of video seems awfully high.