A compact binary inspiral-coalescence GW signal generally depends on 17 parameters (15 for the case of BH-BH binaries), each expressing a property of the binary system itself. Such properties can be intrinsic (like the masses and spins of the components, or the tidal deformability’s in the NS case) or extrinsic, i.e. describing the position and orientation of the system with respect to the observer. A necessary condition for precise determination of such parameters is a good theoretical knowledge of the GW signal, which can be achieved by a synergy among numerical relativity and various analytical perturbative methods, such as the post-Newtonian framework (valid large separation and small relative velocities) or the extreme mass ratio limit. If such theoretical control is achieved, then it is possible determine accurately the sources’ properties from the experimental GW detections (especially if made by more than one interferometer, in order to break degeneracies), and to use them to address several scientific problems such as, to mention a few, studies of population properties of compact binary systems, tests of General Relativity, determination of the speed of GWs, constraints on the expansion history of the Universe, constraints on the neutron star equation of state, hints about the nature of dark matter.