This paper argues that designers of Computer Mediated Communication Systems (CMCs) need to pay attention to the storage, organization and retrieval of conversations. It presents an ethnographic study of ?Bob,? an expert consultant to consultants in a large organization, and examines the ways in which he fashioned what he calls his "external memory pack" from the thousands of conversations he has had via instant messaging, email, and other forms of CMC. Particular attention is paid to the way in which he organizes, searches, and weaves together conversations to achieve his ends. We conclude by outlining the design implications of his use.