It's no surprise ad tech has grown exponentially over the past few years. The Exchange Lab, a programmatic marketplace, recently took a look at just how far the industry has exceeded expectations over the past five years. "It is obvious that ad spend has and will continue to grow through digital platforms, and consistently at a rate faster than we predict," said Exchange Lab chief strategy officer Tim Webster. "The speed of growth in digital marketing naturally brings new challenges, such as viewability [issues] and ad blocking. The industry tends to thrive off shocking predictions; therefore, marketers should evaluate and take considered actions because ad tech continues to show agility in addressing these issues, as it has proven so far."