Search engine optimization (SEO) is the practice of improving a website to increase the quantity and quality of traffic from search engines. SEO helps businesses grow by figuring out what people search for online and creating relevant content that search engines can understand and index. The fundamentals of SEO are simple but effective - it involves optimizing on-page elements like titles and content as well as off-page elements like backlinks to help rank higher organically in search results. While SEO takes ongoing work, it can continue generating traffic over time if done properly by focusing on users' search intents and questions.