  Being able to safely distinguish astrophysical from potential dark matter
(DM) annihilation signals is of utmost importance for indirect DM searches. To
this end, one has to rely on distinctive -- and unique -- spectral signatures
to look for. Internal bremsstrahlung (IB), unavoidable in the presence of
charged annihilation products, provides such a signature. In fact, as it
generically dominates the gamma-ray spectrum expected from DM annihilations, at
high energies, it may well turn out to be more important for indirect DM
searches than the traditionally looked-for line signals. As illustrated in some
detail, the observation of IB signatures would even allow to distinguish
between different DM candidates or to constrain significantly the parameter
space of, e.g., neutralino DM. The gamma-ray contributions reported here are
therefore of great interest for the already launched Fermi/GLAST satellite and
the upcoming new generation of Air Cherenkov Telescope systems like CTA --
which are most sensitive at the high energies where these effects are
particularly important. Finally, radiative corrections may even significantly
alter the positron spectrum from DM annihilations; an intriguing positron
excess recently found by the PAMELA satellite might turn out to be an
indication of the peculiar spectral signature expected in that case.
