The idea to celebrate this chocolate brands 80th birthday is a simple as it is inclusionary. By printing special edition chocolate bar packaging with numbers, from 1-80, the brand itself practically invited everyone who had a birthday to join in celebration. If you'r four, or forty-five doesn't matter - you can have a packet of chocolate made just for you. And we all have birthdays, even that little baby in the crib who hasn't had her first one yet.
Cute idea and the 'case study' here works just as well as an ad.