Software engineers often have trouble coordinating shared work due to poor communication practices. We present results from a large-scale survey of Microsoft employees about their information-sharing communication practices that shows that not all engineers correctly perceive that they have dependents. When they do wish to communicate, personal feelings, social rules, organizational culture, and software-related modularity inhibit and/or shape communications with each group of intended recipients. In addition, a great amount of effort is often required to identify, from a large set of engineers, the small subset who should receive these communications. To help developers with this process, and encourage them to communicate, we created a people investigation and communication tool called CARES: Colleagues and Relevant Engineers’ Support. We developed, deployed, and evaluated our CARES Visual Studio extension several times over a one-year period. After interviewing and surveying over a hundred CARES users, we learned how CARES fit into various engineers’ workflows. Engineers also reported that CARES simplified the process of identifying relevant colleagues and facilitated first contact, and helped them to feel that they were part of a community.