What specific markets set the "price" for Ethereum. I'm assuming it's some type of open market model, but can't find any information on the standard used? For instance, Coinbase displays a price when purchasing; where is this derived from?
Subsequently, what drives the (sometimes drastic) intraday price changes? Supply can't possibly change that much in a short period of time. Is it just "public sentiment" of a few of the more active traders?