All the well known exchanges today have copy trading.

You need to read this before you start to mirror trading: The down side of copy trading

Let me make the image easy for you. Those that you see on the image are copying just a single trader, they begin the trade at different time, those that started early make money because the trader that is copied is making money already. Those that started copying the trader late were losing. That is one of the disadvantages of copy trading. Another disadvantage is that a trader that is making money today that people are copying may be losing tomorrow.