In this talk I will review some general aspects about the different ways of injecting light into a topological photonics system and of extracting information about its dynamics from the emitted light. Rather than just a hindrance, the intrinsically non-equilibrium nature of optical systems can in fact be seen as a promising asset in view of exploring new physics beyond what is normally done in condensed-matter and ultracold atom systems. In the first part, I will review the basic features of the principal pumping schemes used in experi- ments on quantum fluids of light [1] and topological photonics. In particular, I will illustrate how these features have been exploited in recent experiments to highlight different aspects of topological physics. In the second part, I will present some theoretical proposals of new effects that can be studied in state-of-the-art systems of current interest for topological photonics. Our long term goal is to push further the research on topological photonics in the direction of generating strongly correlated states of light in strongly nonlinear systems [2, 3] and observe novel phase transitions in a driven-dissipative context [4]. References [1] I. Carusotto and C. Ciuri, Quantum fluids of light, Rev. Mod. Phys. 85, 299 (2013) [2] E. Macaluso and I. Carusotto, Hard-wall confinement of a fractional quantum Hall liquid, arXiv. [3] R. O. Umucallar and I. Carusotto, Spectroscopic signatures of a Laughlin state in an incoher- ently pumped cavity, to be submitted. [4] J.Lebreuillyetal.,Stabilizing strongly correlated photon fluids with non-Markovian reservoirs, arXiv.