Search engine optimization (SEO) involves optimizing websites to improve their visibility in search engine results. The presentation discusses SEO techniques that can be implemented inside a website, such as specifying keywords, rephrasing text for readability, optimizing HTML, and creating eye-catching content. External techniques include submitting the site to directories, using social networking to promote the site, avoiding penalties for bad practices, and ongoing optimization through analytics and webmaster tools. The goal is to generate unpaid traffic and continuous visitors through high search engine rankings.