Devices that looked and operated like air fresheners were installed on commuter buses in Seoul to lure in customers to their stores.

These machines would release the aroma of Dunkin’ Donuts coffee into the air as the sound of the company’s advertisement was simultaneously played on the buses' speakers. When the radio advertisement ended, the bus conveniently stopped close to a Dunkin' Donuts store.

“In Seoul and South Korea, there is a lot of passion for Dunkin' Donuts, so this offered an opportunity to try something unique and different,” said Jessica Gioglio, public relations and social media manager at Dunkin' Brands.

More than 350,000 people in Seoul smelled the fragrant coffee scent on, let's face it, typically less-than-fragrant city buses. Apparently they liked what they smelled. Dunkin' Donuts reports that visitors to coffee shops in Seoul increased by 16 percent and sales of Dunkin Donuts by bus stops in Seoul increased by 29 percent.

Susan Gilbert, CEO of the online marketing agency Online Promotion Success, said combining the evocative advertising with the added convenience of a nearby store was a brilliant move by the company.