  The empirical scaling law, wherein the total photoabsorption cross section
depends on the single variable eta=(Q^2+m_0^2)/Lambda^2(W^2), provides
empirical evidence for saturation in the sense of sigma_{gamma*
p}(W^2,Q^2)/sigma_{gamma p}(W^2) --> 1 for W^2 --> infinity at fixed Q^2. The
total photoabsorption cross section is related to elastic diffraction in terms
of a sum rule. The excess of diffractive production over the elastic component
is due to inelastic diffraction that contains the production of hadronic states
of higher spins. Motivated by the diffractive mass spectrum, the generalized
vector dominance/color dipole picture (GVD/CDP) is extended to successfully
describe the DIS data in the full region of x=<0.1, all Q^2>=0, where the
diffractive two-gluon-exchange mechanism dominates.
