Part of the story:
"South Korea is one of the most sleep-deprived countries out there. And Seoul is known for epic work commutes. So people doze during their morning subway ride - the problem is how to wake up in time for their stop.
Burger King, which has 202 restaurants in Korea, just ran a small, targeted campaign in Seoul with a quirky answer to that dilemma.
The campaign from Cheil Worldwide offered sleep masks to commuters at five major stations in Seoul. Written across them was a message asking other commuters to wake them up at their particular stop. There were two coupons for free coffee inside the masks, so people could use one themselves and share the other with the person who woke them.
Morning sales at participating stores rose 18.7% in the month from the starting date, Feb. 23, Burger King said. And social-media chatter about the brand jumped 44.5% in the same period."
Fully story here: Why Burger King Gave Funny Sleep Masks To Korean Commuters | Behind The Work - Advertising Age