You will often find that many people confuse marketing with advertising or vice versa. While both components are important they are very different. Knowing the difference and doing your market research can put your company on the path to substantial growth.

Let's start off by reviewing the formal definitions of each and then I'll go into the explanation of how marketing and advertising differ from one another:

Advertising: The paid, public, non-personal announcement of a persuasive message by an identified sponsor; the non-personal presentation or promotion by a firm of its products to its existing and potential customers.

Marketing: The systematic planning, implementation and control of a mix of business activities intended to bring together buyers and sellers for the mutually advantageous exchange or transfer of products.

After reading both of the definitions it is easy to understand how the difference can be confusing to the point that people think of them as one-in-the same, so lets break it down a bit.

Advertising is a single component of the marketing process.

It's the part that involves getting the word out concerning your business, product, or the services you are offering. It involves the process of developing strategies such as ad placement, frequency, etc. Advertising includes the placement of an ad in such mediums as newspapers, direct mail, billboards, television, radio, and of course the Internet. Advertising is the largest expense of most marketing plans, with public relations following in a close second and market research not falling far behind.

The best way to distinguish between advertising and marketing is to think of marketing as a pie, inside that pie you have slices of advertising, market research, media planning, public relations, product pricing, distribution, customer support, sales strategy, and community involvement. Advertising only equals one piece of the pie in the strategy. All of these elements must not only work independently but they also must work together towards the bigger goal. Marketing is a process that takes time and can involve hours of research for a marketing plan to be effective. Think of marketing as everything that an organization does to facilitate an exchange between company and consumer.

Source: http://marketing.about.com/cs/advertising/a/marketvsad.htm