There are many people out there who cannot differentiate between SEO and Internet Marketing. I think there is a distinct difference between them.
SEO involves creating and/or modifying website code or content in accordance to Search Engine Rules and Regulation to reach the top position of Search Engine Result. It involves works such as keyword research, writing meta tags, creating optimum internal link architecture and link building.
Whereas, Internet Marketing does not involve works such as keyword research, writing tags, internal link architecture. Internet Marketing is just another Marketing similar to TV marketing, Radio Marketing Newpaper Marketing.
Internet Marketing involves creating customer based networks and spreading the word of product or service using methods like Social Media Marketing.