Back in the day a shopkeeper might hire a barker to loudly tease the goods found inside a store. That changed with technology, with loudspeakers urging you to stop and look in. With today's technology, the practice of capturing a customer's attention is subtler — so much so a person isn't necessarily distracted by the sound or even realize if they are prompted to move inside by it.
Fast food tastes good. That's why it's bad for you. Kids don't care about that, and (as of 2010) 18% of children between six and 19 are obese. It's probably no coincidence that researchers have found that these kids have logos "branded" into their brains, activating pleasure centers if they even see fast food.