1. A system for dynamically determining a set of relevant rule instances based on a set of context attribute values and a hierarchically organized rule data store, comprising: a directory server of rule instances having hierarchical structure; an attribute data store of said rule instances optimized to provide a set of hierarchically relevant context attribute values, based on the set of context attribute values; and a rules engine configured to provide the set of context attribute values to the attribute data store, and to determine a set of relevant rule instances, based on the hierarchically relevant context attribute values from the attribute data store.