The MACD is an extremely popular indicator used in technical analysis. It can be used to identify aspects of a security's overall trend. Most notably these aspects are momentum, as well as trend direction and duration. What makes the MACD so informative is that it is actually the combination of two different types of indicators. First, the MACD employs two Moving Averages of varying lengths (which are lagging indicators) to identify trend direction and duration. Then, it takes the difference in values between those two Moving Averages (MACD Line) and an EMA of those Moving Averages (Signal Line) and plots that difference between the two lines as a histogram which oscillates above and below a center Zero Line. The histogram is used as a good indication of a security's momentum.
about the MACD.