What are Web Developers /Web Designers?

Web designers are people who conceptualise and plan out the site.

Web developers are the people who use some form of HTML to build the actual pages. A Web developer's other responsibilities could also include optimising graphics for the Web and producing rich media such as Flash, streaming media, or online audio.

A Web Developer builds and maintains websites.

Some people combine both of the roles and create a site from start to finish  designing graphics and webpages, creating the site map and producing the site.