The article provides an interesting history on digital filter design and explains why IIR—infinite imulse response or recursive filters—should be taken in consideration again where FIR filters are typically used. Part of the motivation is that there are now design techniques for recursive filters that guarantee them to be stable and have linear phase (i.e. the waveform of the input signal is preserved) while being much more efficient than finite impulse response (FIR) filters. The references are also worth a read.
PS: Why is there no DSP or signal processing tag?