When we talk about content web products, there are really two broad categories. You have the information web, and then you have lightweight applications.
I’m going to spend time covering the information web because a lot of the programming—and more importantly, the thinking—needed to build web products depends on understanding that side first. It’s often useful to separate things like branding and informational content from functionality that’s focused primarily, or even exclusively, on the application itself. Doing that makes it easier to reason about what you’re building and why.