Traditional marketing refers to established promotion methods like newsletters, billboards, print ads, television and radio commercials that have proven successful over many years. Digital marketing promotes products or brands using electronic media like social media, search engines, email, and web analytics. The key differences are that digital marketing allows real-time tracking of metrics like views and sales, reaches a worldwide audience without time limits, and generally provides a higher return on investment. Traditional marketing has a limited audience, metrics are not measurable, it is time dependent, and return on investment is lower.