Digital marketing encompasses all marketing efforts that use electronic devices and the internet. It allows businesses to connect with customers through various digital channels like search engines, social media, email, and websites. The document then discusses several common types of digital marketing like social media marketing (SMM), pay-per-click (PPC) advertising, search engine optimization (SEO), content writing, email marketing, and affiliate marketing. It also outlines some advantages like global reach, lower costs, and trackable results as well as disadvantages like requiring new skills, being time consuming, and high competition.