I remember seeing a linguistic graph of the US showing how different regions referred to fizzy sweet drinks (here in Australia, that's 'soft drinks'). The predominant usage was 'soda', fair enough, I can see it. Then there was a fair area of 'pop', which sounds cute and archaic to my ears, but fair enough. The confusing one was a swathe of the US south where they're referred to as 'coke', regardless of the actual drink. I remember someone here on HN relating the story of being asked to get some coke, came back with Coke, and being told he got the wrong thing...
The Coca-Cola Company is based in Atlanta, in the South. It's where the drink has existed the longest. Still crazy, but maybe that gives some perspective.
