In a variety of cellular situations, such as in the cell membrane, the segregation of molecular composition is driven by active stresses. We have provided a general framework to describe this, based on an active version of a Flory-Huggins theory.  For the cell membrane, the involvement of new molecular players (PS and actomyosin) and new modes of interaction (transbilayer coupling and contractile stresses), drive the emergence of mesoscale active emulsions. We apply these principles to study the dynamics of these active agencies themselves - this motivates a study of non equilibrium force patterning over large scales.