Activation of the humoral immune system by microbial infections or self-antigens results in the initiation of strong pro-inflammatory reactions. Antibodies of the immunoglobulin G (IgG) isotype play a crucial role in this cascade of reactions, resulting in the clearance of invading microbes and the generation of long lasting immunity. In addition, IgG antibodies feedback on the generation of novel IgG antibodies by activated B cells, impact plasma cell survival, and participate actively in maintaining and returning to the steady state. This review focuses on our current models of how IgG molecules can have this diverse array of activities.