Because the knowledge required for the construction of a complex software system is often widely distributed among its members, programmers routinely engage in collaboration with each other to acquire knowledge resided in the heads of their peers to accomplish their own programming tasks. We call this kind of collaboration situated knowledge collaboration. Situated knowledge collaboration comes with costs and the costs vary depending on the communication mechanism used. To better understand the cost-benefit structure of different communication mechanisms in support of situated knowledge collaboration, we propose the conceptual framework of collective attention economy. The analytic power of the conceptual framework is illustrated in the comparison of two communication mechanisms. Categories and Subject Descriptors D.2.2 [Software Engineering]: Design Tools and Techniques ? computer-aided software engineering. H.5.3 [Information Interfaces and Presentation]: Group and Organization Inte...