Digital marketing refers to marketing through electronic mediums like the internet, mobile, television, and radio. It uses technologies like websites, emails, apps, and social media to engage with customers. There are two forms - pull marketing, where customers actively seek content through searches and visits, and push marketing, where marketers send messages without customers seeking them out, like display ads. Digital marketing offers benefits over traditional marketing like lower costs, a level playing field for businesses of any size, and real-time results and analytics.