While the goals of SEO and pay-per-click advertising are essentially the same: get visitors to come to your site and convert them to either customers, registrants, or achieve other goals in your site, there is some level of coordination between your landing pages and the advertisements you place on Google. By improving the relevance of your landing pages to the message in your advertising, you will be rewarded with a higher 'quality score', which results in lower costs per click and higher conversion ratios.