Over the last few years, first systematic blind searches in the halo of the Milky Way
based on the Sloan Digital Sky Survey data have uncovered a surprisingly large number of
ultra-faint dwarf galaxies, members of a previously unseen class of stellar systems with extremely low
star densities and less stellar content than a typical globular cluster. It is believed that these
optically highly elusive aggregates of shining baryons hold the greatest leverage for testing
dark matter theory and galaxy formation models. I will give an overview about the most recent findings
in this research field and discuss the role of the new Stromlo Milky Way Satellites (SMS) Survey
in providing the empirical input crucial to better understand and possibly reconcile the severe
discrepancies that currently exist between observations and Cold Dark Matter model predictions
on galaxy scales.