While both terms refer to promoting websites by increasing their visibility in search engine results, the main difference between Search Engine Marketing (SEM) and Search Engine Optimization (SEO) is that SEO focuses solely on strategies to help a website rank in organic (unpaid) search results. SEO practices include improving the quantity and quality of content on websites to offer more value to audiences, with the goal to be recognized by search engines as a valuable resource and placed in relevant search results. In the digital marketing community, SEM is often used as an umbrella term for organic and paid strategies that help a website gain more visibility in search engine results. Therefore, SEM may include SEO strategies and paid digital advertising tactics to improve a website’s placement in search engine results.