The knowledge of design experts, mostly tacit, holds tremendous value if made reusable for the right project at the right time. With emerging CMC (Computer-Mediated Communication) technologies, architectural practice has been transformed and faces new opportunities for capturing and reusing tacit design knowledge in a distributed design environment. This paper describes the impact of tacit design knowledge shared and captured by using online, interactive chat-based software. DKM (Dynamic Knowledge Map) has been developed to employ synchronous CMC to assist in the reuse of design experts tacit knowledge in a distributed design environment. The software was tested it in a distributed design environment involving a high degree of expertise and consequent need for applying tacit knowledge. An instrumental case study approach was used for this research. Data were collected and analyzed using both qualitative and quantitative methods to enhance the validity of findings: content analysis, log files, simple statistics, and questionnaires. The results indicate that the interactive chat sessions and archives positively influenced the students design performance by means of tacit knowledge sharing. This research also suggests that the importance of tacit design knowledge may be confidently enhanced through careful design in a distributed design environment.