  HI in and around galaxies provides unique information about the various
processes shaping galaxies: merging, cold gas accretion, feedback. Observations
of galaxies in the nearby universe are beginning to reveal the HI signatures of
these processes by pushing the sensitivity limits of existing radio synthesis
telescopes to their limits. This paper gives a brief inventory of these
signatures. The capabilities of new instruments such as the SKA pathfinders and
precursors is briefly addressed, though ultimately SKA will provide the
adequate sensitivity to find these HI signatures beyond the local universe.
