It is common to see financial site providing MACD in (12,26,9). I was so confused on what those number mean and finally I resolved it today.
12 – is the 12 day moving average of the stock
26 – is the 26 day moving average of the stock
9 – is the 9 day moving average of the MACD!

MACD = 12 day MA – 26 day MA.
When MACD cross above 9 day MA of MACD is buying signal, while MACD cross under the 9 day MA of MACD is selling signal.

This is like taking me an hour to search and read on the detail and finally discover the last number 9 is 9 day MA of MACD instead of 9 day MA of the stock…..