Wiki Describes a Web Developer as:
A web developer is a programmer who specializes in, or is specifically engaged in, the development of World Wide Web applications, or distributed network applications that are run over HTTP from a web server to a web browser.
But a Web Developer is much more than that, web developers bring solutions to the web. Most of the time a developer will build or make an application that solves problems for businesses, corporations, or individual people. A lot of applications out there are also a way to stream line a process, and scripting a process that cuts out the mundane task that a human would have to do.
Stream lining repetitive work is really the back bone to tons of apps out there. And if you are good at executing solutions then you will make an excellent web developer.