[dagw]

One factor that I've noticed is that Americans love ice much more than Europeans. It's not uncommon for them to fill a cup with ice almost to the rim and then add the soda. It would be interesting to see how much actual soda most people put in those 1+ litre ups.

[madcaptenor]

I've seen calorie counts posted on soda fountains. If I recall correctly the fine print says that they figure one-third ice.