  Partonic interpretation of high-energy reactions is known to depend on a
reference frame. Particularly, in the rest frame of the target Drell-Yan
process looks like freeing of the projectile lepton-antilepton fluctuation,
rather than q+qbar -> l+lbar annihilation. The light-cone representation for
Drell-Yan reaction is very similar to that in DIS and exposes a substantial
contamination of soft interactions, which turn out to be dominant in
diffractive production of lepton pairs and in nuclear shadowing. We estimate
the fraction of diffractive events in the total Drell-Yan cross section, which
scales in M^2, and find a substantial deviation from factorization. An
analogous approach is developed for diffractive production of heavy flavors.
