Digital Marketing / Online Marketing:

Digital Marketing is one of the biggest and cost effective digital medium available worldwide. it is marketing or promotion of brands, products, services to the consumers by utilization of internet as a digital medium.

Digital Marketing = Search Engine Marketing + Social Media Marketing + Email Marketing + Referral Marketing + Content Marketing + Design ...

Search Engine Marketing (SEM):

Search Engine Marketing (SEM) is basically the science and art of getting targeted traffic (free and paid) to your website from search engine like Google, Yahoo, Bing or other search engine networks.

Search engine marketing can also defined as a form of internet marketing that involves the promotion of websites by increasing their visibility in the search engine networks through all the activities that bring the free targeted traffic from search engine networks (Search Engine Optimization) and all the activities that bring the paid targeted traffic from search engine networks (Search Engine Advertising)

Search Engine Marketing (SEM) = Search Engine Optimization (SEO) + Search Engine Advertising (SEA)

Search Engine Optimization (SEO):

Whenever you type a query (Keyword) in any search engine and hit the "search" button you get a list of web results called organic (unpaid or natural or free or algorithmic) search results which contain that query term. Users normally tend to visit the websites that are at the top.

Search Engine Optimization (SEO) = Activities That Bring Free Traffic From Search Engines

Search Engine Advertising (SEA):

Search Engine Advertising (SEA) means advertising via search engines. You have two options to advertise via search engines in which the first option is to place your ad on search engine result pages (SERPs) and other is option is to place your ad on the display network of search engines.

Search Engine Advertising (SEA) = Activities That Bring Paid Traffic From Search Engines

Social Media Marketing (SMM):

Social Media Marketing (SMM) is getting targeted traffic (free and paid) to your website from Facebook, Twitter, LinkedIn, YouTube, Google+ or other social media networks.

It's promotion of websites by increasing their visibility in the social media networks through all the activities that bring the free targeted traffic from social media networks (Social Media Optimization) and all the activities that bring the paid targeted traffic from social media networks (Social Media Advertising).

Social Media Marketing (SMM) = Social Media Optimization (SMO) + Social Media Advertising (SMA)

Social Media Optimization (SMO):

Social Media Optimization (SMO) is getting free targeted traffic to your website from Facebook, Twitter, LinkedIn, YouTube, Google+ or other social media networks through various social activities like blogging, posting status updates on social media profiles, participation indiscussion groups, social bookmarking, virals, online reputation management, user rating/polling, user feedback, RSS feeds, sharing buttons, use of video/photo sharing sites and many more.

Social Media Optimization (SMO) = Activities That Bring Free Traffic From Social Media

Social Media Advertising (SMA):

Social Media Advertising (SMA) means advertising via social media. Having ads that appear on Facebook, Twitter, LinkedIn, YouTube and other social media sites that are promoting any brand, product or service. These ads are served by social media advertising platforms where advertisers pay money for showing their ads on social media network pages which are based on various payment models.

Social Media Advertising (SMA) = Activities That Bring Paid Traffic From Social Media (SMA) + All Other Online Display Advertising Channels