Digital marketing is a marketing technique that uses internet platforms like search engines, social media, and websites. It has several advantages over traditional marketing like higher reach, ability to precisely target audiences, lower costs, and potential for high returns. Some key aspects of digital marketing include search engine optimization (SEO), social media marketing, Google Adwords, email marketing, and video marketing. Metrics show digital marketing's massive reach compared to traditional methods and its potential for high user engagement and returns on investment. Popular social media platforms used for marketing are Facebook, Twitter, YouTube, and Google+. Digital marketing career opportunities exist as entrepreneurs, in online marketing roles at companies, or as freelancers specializing in services like website creation and SEO.