The article discusses the effectiveness of digital advertising, citing a story about eBay's advertising efforts and how they were found to be largely ineffective. A study by economist Steve Tadelis found that eBay's ads were not driving significant sales, and that the company was wasting millions of dollars on advertising. The article suggests that the online advertising industry is driven by irrationality and that many companies are unaware of the true effectiveness of their ads. The industry's reliance on flawed statistical methods and a lack of understanding of human behavior contribute to its ineffectiveness.