Revision history provides a rich source of information to improve the understanding of changes made to programs, but it yields only limited insight into how these changes occurred. We explore an additional source of information – program viewing and editing history – where all historical artifacts associated with the program are included. In particular, we suggest augmenting revision histories with the interaction history of programmers. Using this additional information source enables the development of several interesting applications including an influence-recommendation system and a task-mining system. We present some results from a case study in which interaction histories from professional programmers were obtained and analyzed. Categories and Subject Descriptors: H.4[Information Systems Applications]:Information storage and retrieval. General Terms: Measurement.