The RoboPol program has been monitoring the R-band linear polarisation parameters of an unbiased sample of 60 gamma-ray-loud blazars and a "control" sample of 15 gamma-ray-quite ones. The prime drive for the program has been the systematic study of the temporal behaviour of the optical polarisation and particularly the potential association of smooth and long rotations of the linear polarisation position angle with flaring activity at high energies. Here we present the program and discuss a list of selected topics from our studies of the first three observing seasons (2013-2015) both in the angle and in the amplitude domain.