Both pay-per-click and SEO are targeted to get your website placed as close to the top of search engine results as possible. Marketing and SEO are different, yet very, very similar. SEO is considered the main factor in enhancing the traffic of one's website. The concepts of good SEO are hardly a secret. The people who least understand issues with URL structure and SEO are the very people who create them: web developers, programmers, and software developers.
Many long-time SEO's are now looking at the big picture and working with usability analysts. Some SEO are scam artists. I find it interesting that so many newcomers are given the wrong impression that there is one almighty answer to doing well in search engines. SEO are specialized technique used to optimize your website, be Search engine friendly and increase your chances of placing well in searches. But SEO can also be the most profitable method of driving leads because any leads you receive from SEO are free leads.
There are a large number of companies that adopt a fast and unethical approach to SEO known as Black Hat SEO. They use unethical techniques against search engine policies. The best results from SEO are rarely achieved overnight. Black hat SEO is a technique used to fool the search engines to bring more traffic to the website.