When implemented digitally, exponential smoothing is easier to
implement and more efficient to compute, as it does not require
maintaining a history of previous input data values. Furthermore,
there are no sudden effects in the output as occurs with a moving
average when an outlying data point passes out of the interval over
which you are averaging. With exponential smoothing, the effect of
the unusual data fades uniformly. (It still has a big impact when
it first appears.)