Search engine optimization is the most important part of a digital marketing campaign. It is one of the factors (along with social media marketing, email marketing and content marketing) that helps you generate traffic and leads. The majority of web traffic is driven by search engines, and with SEO in place, your website will be listed higher in the search engine results pages (SERPS) than your competition. This can lead to a massive increase in traffic to your site - something that's key in the digital marketing world. The better your SEO, the more traffic to your site, the more leads you'll generate, and the more sales you'll make.