Many Internet marketing agents will tell you that SEO (Search Engine Optimization) and Paid Search (PPC or Pay-Per-Click advertising) are two different mechanisms striving for the same goal – to attract more clicks and visitors to your site. They may even encourage you to use both techniques, just to be safe.

But what they rarely tell you is that both SEO and Paid Search thrive on the existence and quality of one another. To use both should not be a casual suggestion – rather, it’s a necessity for your site to flourish from the get-go. Focusing all of your site’s resources into just one of these techniques and not the other comes at the detriment of both.

SEO encompasses a system of strategies to increase your site’s rankings in the search engine results pages of popular search suppliers such as Google, Yahoo!, Ask, and Microsoft’s Live. These non-paid (organic) search results represent free sources of traffic to your site. Ethical SEO is all about relevance for end users and the search engines – it ranges from keyword-optimizing your HTML page titles and meta description tags to front-end content enhancement to creating a buzz on social websites like MySpace or Twitter.

Paid Search differs from SEO in that you set up your advertising campaign with a particular search engine and proceed to bid on ad space on their search results pages. These ads need to be well-written and highly targeted to speak directly to your customer base.

Of the search engines offering Paid Search management tools, Google AdWords has empirically shown to be the most viable option for businesses of all sizes. According to a Hitwise competitive intelligence study, Google consistently and increasingly receives the majority of the U.S. searches online, trailed by Yahoo!, MSN, and Ask respectively.

Your average cost-per-click (CPC) and ad’s placement are determined by factors such as keyword specificity, relevance of the ad copy, and quality of your landing pages — a little something Google calls the Quality Score. This is where SEO comes in.

Through SEO, you’ll create relevant, keyword dense (but not stuffed) landing pages. The better your SEO, the more relevant your landing pages appear to Googlebot, the higher your targeted ads’ Quality Scores will be. A higher Quality Score means a higher position in the Paid Search listings AND a lower minimum bid for each of your ads. Wouldn’t it be nice to bid only $0.20 for one of the top ad spots instead of $7.00? Over the short and long term, you can see how SEO saves you money as well as increases the volume and quality of your traffic stream.