  Virtual effects from a generic description of physics beyond the Standard
Model in terms of contact interactions, or from large extra dimensions will
modify the observed cross sections for easy to detect final states like lepton
or photon pairs, and can be used to probe scales much higher than the
center-of-mass energy of the partons initiating the interactions. In this note
the sensitivity reach of the Large Hadron Collider to contact interactions in
the Drell-Yan channels and of a Future Linear Collider to contact interactions
and extra dimensions in $e^+e^-$, $\mu^+\mu^-$ and $\gamma\gamma$ final states
are studied. Experimental aspects of the measurements, systematic error effects
and the evolution of the search reach with accumulated luminosity are
considered.
