Search engine optimization, or SEO for short, is the driving power of digital marketing today. Without SEO, there would be no inbound marketing because there would be no search engines to direct your content to the users. Search engines are like old-school phone operators. Users ask to be connected to the content they want and search engines do their best to make the connection. Only instead of one phone line, you get to choose from dozens of different websites that might be what you're looking for.