  We review the status of precision measurements of weak neutral current
interactions, mediated by the $Z^0$ boson, at $Q^2\ll M_Z^2$. They can be used
to extract values for the weak mixing angle $\sin^2\theta_W$, a fundamental
parameter of the $SU(2)_L\times U(1)_Y$ electroweak sector of the Standard
Model. Apart from providing a comprehensive test of the electroweak theory at
the quantum loop level, such measurements allow indirect access to new physics
effects at and beyond the TeV scale. After a theoretical introduction and a
brief overview of the three most precise low $Q^2$ weak mixing angle
determinations, we describe the ongoing experimental program and prospects for
future more sensitive studies. We also compare sensitivities of planned and
proposed measurements to physics beyond the Standard Model.
