We consider some elementary aspects of the geometry of the space of
probability measures endowed with Wasserstein distance. In such a setting, we
discuss the various terms entering Perelman's shrinker entropy, and
characterize two new monotonic functionals for the volume-normalized Ricci
flow. One is obtained by a rescaling of the curvature term in the shrinker
entropy. The second is associated with a gradient flow obtained by adding a
curvature-drift to Perelman's backward heat equation. We show that the
resulting Fokker-Planck PDE is the natural diffusion flow for probability
measures absolutely continuous with respect to the Ricci-evolved Riemannian
measure, we discuss its exponential trend to equilibrium, and its relation with
the viscous Hamilton-Jacobi equation.