The dynamics and organization of many cell surface signalingmolecules such as GPI-anchored proteins are driven by the active dynamics of cortical acto-myosin in juxtaposition with the cell membrane-this has given rise to the Active Composite Cell Surface Model.This suggests a classification of cell surfacemolecules as inert, passive and active,based on their interaction with the active cortical fluid.We show how the active composite cell surface provides a medium and a natural mechanics that enables efficient information processing and computation at the cell surface.