For all the differences between SEO and SEM, they both play important roles in success of today’s businesses. An effective SEO strategy or SEM strategy looks to answer this question by identifying overlooked opportunities. The main difference is that Search Engine Optimization (SEO) is focused on optimizing a website in order to get traffic from organic search results. With SEO, it can take months or even years, before your business begins to rank on the first page of search engines.
SEM is a marketing system that uses paid advertisements in order to increase the visibility of a site on SERPs.
Which is bigger SEO or SEM?
Obviously, the biggest difference is that SEO is an unpaid (or organic) marketing channel while SEM is a paid marketing channel. However, using basic SEO techniques, it is possible to earn higher web traffic levels without spending any money. In comparison, with SEM, you will need to spend money on advertising to generate more traffic which can be considerably more costly. SEM provides quicker results whereas SEO relies on a longer-term approach to achieve better ranking in SERPs.
And as you improve your SEO, your organic search results compound over time, with a rising tide lifting all boats.