This paper explores the significance of tacit knowledge for e-business. Using Nonaka and Takeuchi's knowledge management framework the paper investigates the manner in which tacit knowledge is developed and used within an e-business case study, Amazon.com. Context and relationships emerge as fundamentally important factors in the productive use of tacit knowledge. In order to better understand the reasons why context and relationships should be important the paper extends Arrow's information-based approach to innovation. The paper argues that an understanding of information's private goods character, as opposed to its public goods character, opens up new perspectives on managing relationships and context to improve the utility of tacit knowledge for e-business development.