SEO is the process of getting organic search engine traffic by optimizing websites on-page with elements like titles, descriptions and internal links, and off-page through activities like social media, article submissions and forum marketing. Keywords are the terms or phrases people search for that a site aims to rank for through SEO, by creating pages focused on specific keywords. Most searchers don't look beyond the first page of results, so effective on-page and off-page optimization is important for visibility and traffic.