This source, titled "Understanding Chinese IT through Keywords vol. 027," focuses on the concept of "sinking markets" (下沈市場) in China, referring to provincial cities and rural areas where new business opportunities are emerging as urban markets become saturated. The author, Takefumi Makino, explains how the widespread adoption of smartphones and a shrinking gap in purchasing power between urban and rural populations have made these regions promising targets for companies. The article highlights Pinduoduo, a social e-commerce platform, as a prime example of a business that successfully leveraged the unique characteristics of these markets, such as a preference for domestic products and reliance on social recommendations.