  In this talk \footnote{Presented at ICHEP'98, Vancouver, CA, July 1998}, we
present a recently suggested way on how to analytically incorporate massive
threshold effects into observables calculated in massless QCD. No matching is
required since the renormalization scale is in this approach connected to the
physical momentum transfer between static quarks in a color singlet state. We
discuss massive fermionic corrections to the heavy quark potential through two
loops. The calculation uses a mixed approach of analytical, computer-algebraic
and numerical tools including Monte Carlo integration of finite terms. Strong
consistency checks are performed by ensuring the proper cancellation of all
non-local divergences by the appropriate counterterms and by comparing with the
massless limit. The size of the effect for the (gauge invariant) fermionic part
of $\alpha_V ({\bf q^2},m^2) $ relative to the massless case at the charm and
bottom flavor thresholds is found to be of order 33%.
