As CMB experiments become more sensitive, it becomes possible to expand the scope of the science. I will talk about three new science directions enabled by CMB experiments that all involve searches for missing mass: 1) CMB lensing allows reconstruction of the projected gravitational potential of the visible universe, allowing a careful census of all of the mass in the universe; 2) sub-mm and CMB surveys have uncovered a large population of strong gravitational lenses, which are ideally suited for follow-up observations with ALMA that can map out small fluctuations in the surface mass distribution and probe dark matter on the smallest scales; 3) as surveys that map large areas of sky on a regular basis, it is possible to detect asteroids and dwarf planets, and also any possible new planets in the outer solar system, all through their thermal emission at mm-wavelengths.
