New York (CNN Business) A sweeping internet disruption on Thursday briefly took out a wide range of major corporate websites — from FedEx and Delta Airlines to HSBC and McDonald's.

The McDonald’s Happy Meal turns 40 this month, and the nostalgia for those “happy” memories of unboxing a toy surprise with a side of fries is the backbone of a promotion McDonald’s is running in November.

Why is McDonald’s more successful than Burger King or Wendy’s? Their food isn’t any better; their prices are about the same. Yet McDonald’s sales in 2018 dwarfed those of its rivals with over $20 billion compared to about $1.6 billion for both Wendy’s and BK.