  We determine the order of magnitude of the $n$th $\ell_p$-polarization
constant of the unit sphere $S^{d-1}$ for every $n,d \geq 1$ and $p>0$. For
$p=2$, we prove that extremizers are isotropic vector sets, whereas for $p=1$,
we show that the polarization problem is equivalent to that of maximizing the
norm of signed vector sums. Finally, for $d=2$, we discuss the optimality of
equally spaced configurations on the unit circle.
