  I discuss the implications of the Parkes HI Multibeam Southern Sky Survey for
cosmology. It will determine the local mass function of HI clouds, detecting
several hundred per decade of mass. Each of these will come with a redshift
and, for the more massive clouds, an estimate of the velocity width. This will
provide an ideal database for peculiar motion studies and for measurements of
biasing of galaxies relative to the underlying matter distribution.
