SEO is a three letter acronym -short for Search Engine Optimization. Search engine optimization is about trying to rank higher in search engines. To rank higher you make changes to your website that makes it easier for search engines to understand your content. Also, it can mean getting links from other websites.
SEM stands for “search engine marketing.” It is the process of gaining traffic or visibility on search engines. The phrase is also sometimes shortened to “search marketing.” SEM is an umbrella term that covers two broad areas:Gaining traffic through free SEO efforts gaining traffic through paid search advertising.
Social media marketing is typically designed to target a user’s known preferences. For example, sponsored Facebook ads are based on posts by the user or the user’s friends. Other sites, such as YouTube, have commercials before a free video that a user must watch before viewing the video.