Attribution remains an issue for marketers across platforms and channels but with footfall they can see tangible and attributable results, according to Rob Weston, brand and marketing director at UK retailer Marks & Spencer. And mobile, with its associated location-based marketing possibilities, is playing a crucial role in helping M&S change people's actual behaviour, he told the MMA London Forum (June 2017).

The importance of mobile across the customer journey should be evident to everyone by now, he observed: 90% of Facebook's traffic is mobile, as are 60% of Google searches and 70% of Amazon's sales. And yet, the time spent-ads gap persists, with mobile taking 61% of a person's average media time while only 38% of digital adspend goes on this channel.

“From our own perspective," he said of Marks & Spencer, "we see 21% of traffic come through mobile but that accounts for only 3% of sales; 34% of traffic comes through laptops and desktops but that is only 12% of sales." Footfall, at 45%, remains the single biggest form of traffic and accounts for the great majority of sales (85%).