1. A method, comprising: storing, at a computer system, information that implements a namespace having a plurality of objects, wherein the stored information includes data for various ones of the plurality of objects that is indicative of attribute values for one or more of a plurality of object attributes; receiving, by the computer system, an object associated with a user-defined attribute value; adding, by the computer system, the object associated with the user-defined attribute value to the namespace; receiving, by the computer system, first and second queries of the namespace that respectively indicate one or more attribute values and organization of query results, wherein the first query indicates relative levels of object attributes within a first hierarchy of object attributes and wherein the second query indicates relative levels of object attributes within a second hierarchy of object attributes; generating, by the computer system in response to the first and second queries, respective first and second sets of access data usable to access objects in the namespace that have one or more attribute values that match the one or more attribute values specified by the respective first and second queries; and transmitting, by the computer system, the first and second sets of access data to one or more second computer systems associated with the first and second queries; wherein the first and second sets of access data are organized using the respective first and second hierarchies, and wherein the second hierarchy includes a given attribute at a level that is different from a level of the given attribute in the first hierarchy.