Q. What is the advantage of a two-stage overloaded RC coupled amplifier over a single stage one? What are it's uses?

It is a frequently encountered configuration. Here, the transistor switch Q2 is driven not directly by a gating signal, but rather by the output of  a preceding transistor Q1. The transistor Q1 has, applied to it, a gating signal which drives this transistor alternately from cutoff to clamp and back again. Accordingly, in the absence of the loading effect of transistor Q2, the signal at the collector of  Q1 would be a gating waveform of the same form as the input signal, except inverted polarity. When Q1 is cut off, the output impedance of Q1 is equal to the collector-circuit resistance. When transistor Q1 is in saturation, the output impedance is the parallel combination of collector-circuit resistance and the collector saturation resistance   , and hence nominally equal to the latter. The circuit is designed as shown below.