From personal experience, I can tell you that the terms developer and engineer are being used interchangeably in the industry. Most “software” our company develops interfaces with the web in some form or fashion, therefore, our “engineers” are both “web developers” and “software engineers”. I put them in quotes because they don’t mean anything in the grand scheme of things.
At the end of the day, you are going to build a product or provide a service using programming languages that all follow the same fundamental principles of variables, functions, arrays, lists, etc. The real difference comes in the form of architecture. Where do you offload your data? or storage? How much memory to allocate? and so on and so forth.
In my opinion, a good “software engineer” and/or “web developer” is technologically agnostic. They understand all of the tools at their disposal, and they only use the right tools for the job.
Rey’s original reply can be found here on Quora.