  In a recent Letter [PRL, 107, 047208 (2011)], Zorko et al. report on an
"unexpected inhomogeneous magnetism" related to "a peculiar fragility" of the
resonating-valence-bond (RVB) electronic state in the spin-1/2 quantum magnet
CuNCN. Here, we show that: i) the spin model of the anisotropic triangular
lattice (ATL), as proposed by Zorko et al., does not apply to CuNCN; ii) this
model does not support the proclaimed RVB ground state in the relevant
parameter range; iii) the magnetic state of CuNCN is not necessarily
inhomogeneous.
