We investigate the use of optical photometric variability to select and identify blazars in large-scale time-domain surveys, in part to aid in the identification of blazar counterparts to the ~30% of gamma -ray sources in the Fermi 2FGL catalog still lacking reliable associations. To test the efficacy of this approach, we apply this method to optically variable LINEAR objects that fall within the several-arcminute error ellipses of gamma -ray sources in the Fermi 2FGL catalog. We find that the suggested radio counterpart to Fermi source 2FGL J1649.6+5238 has optical variability consistent with other gamma -ray blazars and is likely to be the gamma -ray source. Our results suggest that the variability of the non-thermal jet emission in blazars is stochastic in nature, with unique variability properties due to the effects of relativistic beaming. The variability-based selection method presented will be useful for blazar identification in time-domain optical surveys and is also a probe of jet physics.