RE: Yoghurt question
I'd say stuff like number of shelves and overall shelf space pretty much varies by what store you're in. The Meijers I go to (fairly large grocery store) has about three shelves of yogurt, maybe about... 7-8' long in an open refrigerated case with no doors/lid. Smaller groceries will have cases that are more compact.
Yogurt is most often sold by the individual serving cup (some accompanied by mix-ins of granola, candy bits, etc.) but it's also sold in portable tubes ("Go-gurt!"), packs of four in various flavors as well as richer "creme" style yogurt, by the quart (usually in limited flavors like plain or vanilla), plus some stores will also carry drinkable yogurt/kefir in various flavors.
I've been to France, and they definitely have more variety of flavors over there than we do. Also, the majority of the yogurt sold here is low-fat or non-fat, finding organic and/or whole milk yogurt can be a bit of a challenge in some areas. When I buy it, I generally go for Trader Joe's Greek style yogurt, or Total Fage brand, whole fat.
This would be in southwest Ohio, if that relevant. :)