MACD Histogram is a tool not usually used by many traders who are interested in MACD Trading .. however when you use the  Histogram you can anticipate Divergence Signals before the Moving averages of the MACD indicator cross over .. 

In this video we will have some examples to learn how to read MACD Histogram signals and how exactly it  is giving earlier alarm that the MACD is going to change it's direction through noticing the sloping line of the Histogram ..