  The significance of thermal dilepton radiation at intermediate invariant
masses (1GeV<M<3GeV) in ultrarelativistic heavy-ion collisions is investigated.
At CERN-SpS energies, a consistent explanation of the excess observed by NA50
can be given. At RHIC energies the thermal signal is dominated by early
emission indicative for QGP formation. Chemical under-saturation effects and
the competition with open-charm contributions are addressed.
