Royal Dutch Shell is in the oil extraction business but it's also one of the largest single branded retailers in the world, with a footprint in 80 countries and 44,000 stations around the world. That makes it bigger than McDonald's or Starbucks, observed Oliver van Bilsen, Global Head of Digital - Retail, Fuels & Lubricants. Some 30 million people enter its stores every day and the brand has a digital relationship of some sort - via loyalty programs, CRM, social media - with 25% of them, he told the MMA London Forum.

In fact, he added, the digital customer experience is becoming the main differentiator for brands, a trend that is developing in three ways.

1. Better CX

"Increasingly, we are not comparing ourselves with our direct competitors," he said. "We are looking towards other brands that are using digital to really transform their customer experience." And the same is true of customers, who measure brand digital experiences against the likes of Uber or Amazon.

2. App partnerships