David Griner of Adweek interviewed Marketing VP Molly Catalano on how the burger-chain went from word-of-mouth only marketing strategy to embracing online platforms for promotion.

The most interesting thing we thought, was that a big part of their Instagram success was user-generated content – that means, using photos from their visitors.

It's not true actually. This is what Catalano had to say about it

But now people take pictures of every single meal. And amazingly, people take good photos of our burgers. In social, we use mostly user-generated content.