Long-lived electronic and nuclear spin states have made nitrogen-vacancy (NV) defects in diamond a leading candidate for solid-state quantum information processing. Moreover, their coherent optical transitions open opportunities for quantum communication. This talk will consider the motivation and requirements for optically-networked quantum devices, and explore challenges and opportunities for realizing them in diamond. In particular, the resonant excitation and emission in these defect centers enables single shot spin detection as well as observation of two-photon quantum interference; these two critical capabilities pave the way towards measurement-based entanglement between remote NV centers.