As consumerism grew, it also became possible to sell products solving problems that were hardly recognized as such, let alone matters of life and death. Demand was engineered by showing not so much that the product would solve the problem but that the problem existed at all. Bringing subconscious anxieties to the fore was the inspired brilliance behind the great campaigns for mouthwash and toothpaste, two products largely unknown before the 1920s.

Tim Wu, The Attention Merchants, loc. 189