While the roll-out of Walmart’s mobile loyalty app Savings Catcher, has tended to focus on its receipt scanning feature, which generates price match coupons, the app's long-term vision is to gather enough data to be able to do your shopping automatically.

Only 0.6% of online shopping is driven by social media, compared to e-mail, which drives 27%. Can Facebook’s Buy button, integrated into newsfeeds, encourage people to spend more when they're on social media? And are retailers really welcome on such a personal platform?

While Amazon has sold as many as 306 items a second in the past, the company is consistently at the forefront of e-commerce innovation. Launched in July 2014 to little fanfare, Amazon integrated a Video Shorts category into its Amazon Prime Video service, and made it shoppable.

“Google policy is to get right up to the 'creepy' line and not cross it,” says the company's CEO. But when does insightful personalisation become intrusive? And how do brands build lasting relationships with consumers concerned about being spied on?