In layman's terms, cell bombing splits a texture into multiple pieces, and then offsets those pieces ever so slightly to essentially randomize the pattern of a material. This works incredibly well for organic textures such as grass, dirt, rocks, etc. and not so well for synthetics (bricks, wood boards, etc.). See here:
TrainSim-Matt Just wanted to make sure you know of this technique. As long as you know of it, my job is done. It's on you whether to utilize it or not, but it's stupid simple to implement, does 0 to performance, and the results are stunning.