This document discusses architecting multi-sided businesses. It begins by explaining that modern businesses need to operate in multiple markets simultaneously and satisfy different stakeholders. The emerging response is to configure the enterprise as a platform of services rather than a traditional value chain. However, this transformation involves profound architectural challenges. It then discusses various topics related to architecting multi-sided businesses including viewing the supply chain as a stack, challenges with stack design, and strategic choices regarding where to position the business in the stack. The document emphasizes the importance of understanding indirect relationships in multi-sided markets and delivering indirect value in addition to direct value.