SEO/SEM
SEO is sometimes used as an umbrella term that includes SEM, but because SEM refers strictly to paid advertising, they are actually separate. SEM is about getting traffic via paid ads, and SEO is more about acquiring, monitoring and analyzing organic traffic patterns.
Search Engine Optimization
SEO stands for search engine optimization — that much has stayed the same. It refers to techniques that help your website rank higher in search engine results pages (SERPs). Learning SEO is hard because there is a lot of information to read about search engines and how the optimization process works, and this can be overwhelming at first.
Search Engine Marketing
Search engine marketing (SEM) involves marketing a business through the use of paid advertisements and using keywords and phrases throughout the content. Search engine marketing, or SEM, is one of the most effective ways to grow your business in an increasingly competitive marketplace.
Search engine marketing (SEM) is a digital marketing strategy used to increase the visibility of a website in search engine results pages (SERPs). While the industry term once referred to both organic search activities such as search engine optimization (SEO) and paid, it now refers almost exclusively to paid search advertising. Search engine marketing is also alternately referred to as paid search or pay per click (PPC).