Julia Set points to this “Pop” vs. “Soda” academic study.
Using the World Wide Web to gather and process data from across English-speaking North America, Alan McConchie plotted the regional variations in the use of the terms “Pop” and “Soda” to describe carbonated soft drinks.
One of the more interesting discoveries (for me at least) is the fact that so many people in the South say “Coke” when they mean soda. I guess it shows the power of advertising, especially advertising with billions of dollars behind it.