Digital marketing refers to using various digital channels and technologies like the internet, mobile devices, social media, and email to promote products and services to target audiences. It involves tactics like search engine optimization to improve website visibility, pay-per-click advertising, social media marketing, content marketing, email marketing, influencer marketing, affiliate marketing, online reputation management, mobile marketing, and using analytics to measure campaign performance. The goal is to engage customers and build the brand through relevant content and interactions across different digital platforms.