Digital marketing, also known as online marketing, encompasses a range of strategies used to promote brands via digital channels, including SEO, social media, and email marketing, allowing businesses to connect with both existing and potential customers. Key components include SEO for organic ranking, SEM for paid visibility, content marketing for engagement, and various advertising models like PPC and affiliate marketing. The advantages of digital marketing include global reach, cost-effectiveness, easy learning, effective targeting, and the ability to utilize multiple strategies and content types.