I've never heard "rotary" used where I live or anywhere I've gone. Actually, that's the first time I've heard it used for something other than a telephone.

A few of the people I know will call it a "roundabout", and I do sometimes, when I'm feeling British Most of the time I say "traffic circle".

I'm not sure what you mean about "anymore".

My mom works at National Geographic, and we have one of their HUGE atlases. There's a section on US dialects, in which you can see all the crazy terms areas of the US has for different things. Some are pretty weird.

Oh, and one last thing. Coca-cola is SODA