This document discusses search engine optimization (SEO) and its various techniques. SEO is the process of optimizing websites to rank higher in organic search results. There are two main types of SEO - on-page optimization which involves optimizing individual webpage content and code, and off-page optimization which focuses on building backlinks through techniques like guest posting. The benefits of both on-page and off-page SEO include increased traffic, exposure and rankings. White hat SEO uses ethical techniques for long-term ranking while black hat SEO uses unethical techniques for quick gains and risks website bans. SEO has grown significantly in recent years with billions of searches conducted each month.