Digital marketing is the promotion of products or brands using electronic media like the internet. It faces challenges like consumers using multiple devices and channels, intensifying competition as digital marketing becomes more cost-effective, and managing large amounts of data. To be successful, digital marketing must manage both digital and traditional channels, allow dynamic customer interaction, extract value from big data to understand customers better than competitors, and provide consistent, coordinated experiences for customers across channels. It requires measuring, monitoring, and testing performance with speed and accuracy.