Heck yeah, there is. Think of SEM as buying traffic and SEO as earning traffic. Because both serve the purpose of promoting site visibility and driving online traffic, SEO is sometimes considered a subset of SEM in general. Nevertheless, they are two very different approaches to achieving a common goal. When visitors reach a site via SEM or “paid search,” it is referred to as paid traffic. Likewise, when visitors reach a site via SEO, it is referred to as organic traffic. Both are often used hand-in-hand to maximize online marketing efforts.
Search Engine Optimization takes place on the web development side of things. Basic SEO involves the use of relevant keywords in the site’s content, URLs, and page titles. It is important to have relevant keywords so that search engines can identify which websites to display when users search related terms. The higher the rank in search engine results pages, the easier the website is for visitors to find, which translates into more traffic to the site.
Search Engine Marketing involves paid ad listings (e.g., Bing and Google AdWords) that are displayed at the top and margins of search engine results pages. Because it is a long, competitive process to earn ranking through SEO, paid search is a surefire way to gain exposure in search results. However, being that it costs money each time a user clicks on an ad, which is why it is often referred to as pay-per-click (PPC) or cost-per-click (CPC), paid search a less sustainable way to generate traffic to a website.