  Since the work of Hartle in the 1970s, and the subsequent development of the
the Membrane Paradigm approach to black hole physics it has been widely
accepted that superradiant scattering of gravitational waves bears strong
similarities with the phenomenon of ``tidal friction'' (well-known from
Newtonian gravity) operating in binary systems of viscous material bodies. In
this paper we revisit the superradiance-tidal friction analogy within the
context of ultracompact relativistic bodies. We advocate that as long as these
bodies have non-zero viscosity they should undergo tidal friction that can be
construed as a kind of superradiant scattering from the point of view of the
dynamics of an orbiting test-body. In addition we consider the presence of
anisotropic matter, which is required for at least some ultracompact bodies, if
they are to sustain a radius very close to the gravitational radius. We find
that the tidal friction/superradiance output is enhanced with increasing
anisotropy and that strongly anisotropic systems exhibit an unconventional
response to tidal and centrifugal forces. Finally, we make contact with the
artificial system comprising a black hole with its horizon replaced by a mirror
(sometimes used as a proxy for ultracompact material bodies) and discuss
superradiance and tidal friction in relation to it.
