  We investigate interactions between spins of strongly correlated electrons
subject to the spin-orbit interaction. Our main finding is that of a novel,
spin-orbit mediated anisotropic spin-spin coupling of the van der Waals type.
Unlike the standard exchange, this interaction does not require the wave
functions to overlap. We argue that this ferromagnetic interaction is important
in the Wigner crystal state where the exchange processes are severely
suppressed. We also comment on the anisotropy of the exchange between spins
mediated by the spin-orbital coupling.
