mCommerce isn't really the standard unit of an e-commerce store, but it's a big piece of the puzzle. mCommerce just means buying stuff using your phone or tablet. E-commerce covers everything , whether you're shopping on your laptop, desktop, or phone. That said, since tons of people shop on their phones these days, most online stores make sure their mobile version works super well. So yeah, mobile's a big deal, but it's not the whole thing.