Digital marketing is the process of building and maintaining customer relationships through online activities. It consists of several key components, including search engine optimization (SEO), pay per click (PPC) advertising, and social media marketing (SMM). The goals of digital marketing are to reach the right audience, engage customers, motivate action, and generate sales or leads in a cost-effective manner. Measurement of digital marketing success includes calculating return on investment using tools that track metrics like website traffic and sales conversions.