The search for relevant information is often hindered by the initial difficulty in formulating precise requests, and because much knowledge is actually tacit and thus not easily accessible. Asking for human assistance is the usual response to these problems, but one can develop computer systems to help locate the right persons in the search for information. We describe the structure and functioning of a collaborative, distributed search system designed to emulate the information-gathering functions of social communities. Such systems can be used to create virtual communities as well as to improve information retrieval.