A Search Engine is the process of using a keyword or specific phrase to search the entire internet by using the sites Search Engine Database (Google, Yahoo, etc).
If the website is not indexed within the database of a particular Search Engine, it may not come up in a search though... even if the user enters the URL perfectly. Another thing to understand is that if a website has not been submitted to Search Engines, optimizing that website may be ineffective.
Internet Marketing - which is also referred to as online marketing or Emarketing, is marketing that uses the Internet. The World Wide Web has brought many unique benefits to marketing including the low cost in distributing information and media to a worldwide audience. The interactive nature of Internet media, both in terms of instant response, and in eliciting response at all, are both unique qualities of Internet marketing.
Internet marketing ties together creative and technical aspects of the internet, including design, development, advertising and sales. Internet marketing methods include search engine marketing, display advertising, e-mail marketing, affiliate marketing, interactive advertising, blog marketing, and viral marketing.
Internet marketing is the process of growing and promoting an organization using online media. Internet marketing does not simply mean 'building a website' or 'promoting a website'. Somewhere behind that website is a real organization with real goals.
Internet marketing strategy includes all aspects of online advertising products, services, and websites, including market research, email marketing, and direct sales.