What makes "zavarka" so important is that it's easy to measure how concentrated you want your tea to be. It's more difficult to achieve with a teabag. Though, I must note, hardly anyone here makes zavarka anymore.
Russia is the land of hot tea, US is the land of iced tea. This must be the crucial difference between the two; the rest just follows...
Here in South Australia, it's often said (Wikipedia's source page from news.com.au is a 404 now though) that a particular brand of iced coffee out-sells Coke.
Sounds like Turkish tea, which we drink at the office every day.