What's the Difference Between SEO and SEM? The main difference is that Search Engine Optimization (SEO) is focused on optimizing a website in order to get traffic from organic search results. On the other hand, the goal of Search Engine Marketing (SEM) is to get traffic and visibility from both organic and paid search.

Is SEM or SEO more important?

With SEO, it can take months or even years, before your business begins to rank on the first page of search engines. And this is why SEM is better for testing than SEO… Because you can immediately turn SEM paid ads off and on, it's a great strategy for testing.