Donald0708
shared author's MetaQuotes article
关于信号订阅很不错的讲解
General information on Trading Signals for MetaTrader 4 and MetaTrader 5 
MetaTrader 4 / MetaTrader 5 Trading Signals is a service allowing traders to copy trading operations of a Signals Provider. Our goal was to develop the new massively used service protecting Subscribers and relieving them of unnecessary costs.