Email marketing has always focused on performance. Early on, marketers began tracking and improving performance in terms of opens, clicks, and -- ultimately -- ROI. In many ways, standalone email advertising remained a different story. Still, this medium has great potential to fit in with the performance-based media buys many agencies and brands prefer.

The explosion in digital and emerging media channels has brought a huge volume of rich, but complex, data sources. With big data comes the promise of better decision-making information and measurement of marketing performance. A recent study by the Columbia Business School and NYAMA found that 91% of senior corporate marketers believe that successful brands use customer data to drive marketing decisions, improve marketing performance and increase customer acquisition.