Most marketers want to get the most out of both organic and paid search. Existing sites are getting more attention as marketers make sites search-engine-friendly (or even search-engine-maximized) as well as user-friendly. Any search engine marketer can tell you SEO (define) requires compromise in areas such as layout and copy length, style, and flow.

Yet, marketers recognize such a compromise can result in a great experience for spiders and users alike. After taking into account a site's search-engine-friendliness and adapting copy and design, you may have made compromises in user-friendliness and conversion. These compromises may yield thousands of new, targeted visitors to your site. The navigational structure helps both search engine spiders and human visitors understand the breadth of your site's offerings. A bit of conversion loss as part of SEO efforts is generally OK.

Paid search marketing campaigns provide something SEO doesn't: complete user experience control. When you pay for clicks, your ability to afford high positions is directly related to your ability to meet marketing objectives with each and every inbound clickstream. Those objectives usually include a basket of conversion behaviors, including lead generation, purchase, and site immersion (to indicate early-stage, research-related buying behavior). The least desirable behavior is clicking the back button.