Understanding MACD?

Hello all.

I am trying to better understand the full capabilities of the MACD. I ahve been successful using this indicator but never truly understanding what it is telling me.

I know you look at the indicator to take positions based on crosses of the signal line. Cross above signal line go long, and cross below signal line go short. But some other referenced sites about this that add in about the importance of the zero level on the indicator. For example, if the main line cross below the signal line and it is above the zero level then this is a strong signal but if the two averages are below the zero line and they cross, then you shouldn’t take a short. The opposite for the long position. Also it states trades that have the two averages close to the zero line then crosses are not reliable. Thanks to anyone that could provide me more information on this. Have a good one.

Adam

Heres a good link someone else posted in this forum

Moving Average Convergence/Divergence (MACD) - StockCharts.com

That is everything I need to know. Thanks!