How does cryptsy.com allocate trades for many orders with same price
At Cryptsy the order is First In First Out influenced by the account's trading history. If the server were to receive buy orders at the same time assuming there is enough coins at the specified price to fill the orders, the server looks at each account and the one with the most trading history gets processed first, then in order to the account with the least trading history. I work for Cryptsy, I'm Brad!