Essentially what’s different from a full stack web developer and another web developer is a deeper understanding on the underlying web technologies, the ability to run a complete network & hosting structure, and a broader understanding of parallel technologies.
Part 3 - The Web Application
This is where things get interesting. At least, this is where end users start to see stuff!
Here is where the developer defines your web application and creates the models that represent your data, the business logic to make the data work in usefull ways and the framework that coordinates the model the logic and the user experience.
Not only does a web developer need to know how to do all of these things, they must also know the best way to optimise things like images, video, style sheets and much, much more!