What is the relationship between SEO and SEM ?

SEM is a more expansive term than SEO and describes all strategies ensuring your website ranks well in search engine rankings and increases the number of site visitors. By extension, SEM can include social media optimization (SMO) and social media marketing (SMM).

SEO is the process of optimizing your web site for the purpose of getting free traffic from search engines.
SEM is the marketing process with a goal of getting more visibility in search engines either by getting more free traffic (SEO) or paid traffic.

SEO or search engine optimization is the process of optimizing your website in search engines. The process helps to build your online identity and reputation to benefit your online business.

SEM stands for search engine marketing. It is the process of promoting your website in various search engines to build its popularity and reputation. Search engine optimization and social media optimization are two major processes used for search engine marketing.

SEO is a part of Search Engine Marketing (SEM) and SEM forms a part of the expansive field of Internet marketing. Internet marketing, online marketing and web marketing consider all factors related to the marketing of products or services over the Internet. Internet marketing is not just promoting a website. It also includes all the creative and technical aspects of design, development, advertising, and sales on the Internet.

SEM is a more expansive term than SEO and describes all strategies ensuring your website ranks well in search engine rankings and increases the number of site visitors. By extension, SEM can include social media optimization (SMO) and social media marketing (SMM). SMO is the use of social media to spread news about your website by participating in social networks