  The high frequency component in blazars is thought to be due to inverse
Compton scattered radiation. Recent observations by Fermi-LAT are used to
evaluate the details of the scattering process. A comparison is made between
the usually assumed single scattering scenario and one in which multiple
scatterings are energetically important. In the latter case, most of the
radiation is emitted in the Klein-Nishina limit. It is argued that several of
the observed correlations defining the blazar sequence are most easily
understood in a multiple scattering scenario. Observations indicate also that,
in such a scenario, the blazar sequence is primarily governed by the energy
density of relativistic electrons rather than that of the seed photons. The
pronounced X-ray minimum in the spectral energy distribution often observed in
the most luminous blazars is discussed. It is shown how this feature can be
accounted for in a multiple scattering scenario by an extension of standard
one-zone models.
