SEM versus SEO: What’s the difference?
Generally, “search engine marketing” refers to paid search marketing, a system where businesses pay Google to show their ads in the search results.
Search engine optimization, or SEO, is different because businesses don’t pay Google for traffic and clicks; rather, they earn a free spot in in the search results by having the most relevant content for a given keyword search.
Both SEO and SEM should be fundamental parts of your online marketing strategy. SEO is a powerful way to drive evergreen traffic at the top of the funnel, while search engine advertisements are a highly cost-effective way to drive conversions at the bottom of the funnel.