Information retrieval augmented by the use of communication relationship data

Information-retrieval is optimised by modifying a query using information based on users communication relationships. Users interactions and relationships with each other are tracked by a 'relationship analyser' RA that queries information sources IS, such as e-mail logs, organisation charts, calendar entries, phone logs, etc. A data structure is created for each user reflecting the intensity of communication relationship with other users, and modified over time. A relationship group is defined based on the data structure and preference or importance ratings for each type of communication relationship that includes each user's group of highest-priority other users. A derived relationship group may also be defined based on high-priority users of a user's highest-intensity relationships. The RA then acts as a proxy for user queries, and may modify queries and create persistent data stores or store the results of queries or sub-queries in order to improve system performance: for example, shortening retrieval time, prioritising information, propagating updated information among closely related users. A way to derive a relationship group based on subject lines of communications, or other text-based content of communication-related information, is also described.