  We perform the two-loop analysis of the 1/Q power corrections to jet-shape
variables. This step is necessary for producing reliable theoretical
predictions for the relative magnitudes of genuine confinement effects. We show
that the rescaling factor recently derived for the thrust case (the Milan
factor) remains the same for the class of observables which includes the
C-parameter, invariant jet masses, jet broadening and the energy-energy
correlation measure. We list the expressions which should be used for
extracting 1/Q power effects in jet shapes.
  We also envisage large non-perturbative effects, characterised by fractional
powers of Q, in certain semi-inclusive observables such as the height of the
spectrum of Drell-Yan lepton pairs with invariant mass Q and transverse
momentum Q_t=0, and back-to-back energy flows in e^+e^- and DIS.
