To understand the difference, you will need to know what is SEO and SEM first.
But in this article, I will only elaborate the basic information for both SEO and SEM as my purpose is to show you what constitutes the difference between them.
SEO known as Search Engine Optimization is a process that helps the business owner to optimize their website and increase their visibility in the search engine by ranking their website in the first page of the search engine which in turn hopes to increase more traffic to view their website and engage in buying their products or services.
There are quite a few steps to do for your website which involves On-site SEO and Off-site SEO just to achieve the best SEO results for your website and rank first in the page ranking.
For Off-site SEO, it refers to the process that will help to increase the website page rankings.
Building quality backlinks, the link building, writing blogs or articles, social bookmarking, guest blogging and social media marketing are usually the common methods of Off-site SEO strategy that will influence the page ranking of the website.
In short, SEO is to get your website from the “free and organic” search results, improve the page rankings in the search engine and also ensure that your website will appear in the first page when people key in the related keywords in the search engine.
For SEM short form for as Search Engine Marketing which is also known as “paid search” is a method of online marketing that help business owners to promote their website by purchasing advertisements on the search engines through SEM process such as PPC (Pay Per Click), Paid search advertisements, PPC (Paid Per Call), CPC (Cost Per Click) and CPM (Cost Per Impression).
The most popular method for SEM is Pay Per Click which the business owners will compete online via the search marketing platforms such as Google Adwords, Yahoo Search Ads or Bing Ads and pay for the advertising space in the search engine results that is usually the first page.
Pay Per Click for SEM can be quite costly to some business owners as he or she will need to pay an amount of money each time the visitor clicks on the advertising website.
Thus the main difference between SEO and SEM is that Search Engine Optimization is part of the Search Engine Marketing process whereas Search Engine Marketing has an additional process of Paid Search but also include components of On-site SEO such as SMM (Search Media Marketing).
While both Search Engine Optimization (SEO) and Search Engine Marketing (SEM) are related, it is best to understand the difference to avoid any misunderstanding when applying the terms in your career or business.