Code:

This is where your product is selling code. Like software. It can replicate extremely fast.

Media:

This is where you create media. Like videos, or articles, or VR experiences. It can replicate extremely fast because it's delivery is based on code.

Product:

This is where your product is a physical product. Like a book or car. You can make a bunch at one time then sell them all.

People:

This is where your product/service goes through people. Like a marketing agency or team of lawyers. This is more complicated to replicate, but often has the biggest moat from competition.