The key difference is that multichannel marketing includes a limited selection of content channels, while omnichannel marketing includes all of them. By definition, multichannel means “many channels” and omnichannel means “all channels.” Think of omnichannel marketing as covering your entire customer journey map, but multichannel marketing as narrowing down on a specific point A to point B.
Also, multichannel marketing focuses more on engagement within the different channels, while omnichannel marketing focuses on comprehension and a seamless experience for your customers.
Another aspect to consider is the retail presence of your products. Multichannel retail is the distribution of products in multiple channels: for example, selling goods on a website as well as in a physical store. Omnichannel retail, however, takes it further by considering the needs of customers and reaching them where they are, through all available channels. For instance, that could include integrating ads in at-home streaming experiences, rather than waiting for them to visit a store. Multichannel retail is a straight line from the brand to the customer, whereas the path of omnichannel retail is more fluid or circular.