A system and techniques are described for creating member private data in a global namespace. According to one aspect, first data that is associated with a key is stored in a repository shared by multiple members. After the first data has been stored, second data that is associated with the key is stored without overwriting the first data. Mapping data is stored. The mapping data maps the key, relative to a first member, to a first data structure that stores the first data. The mapping data also maps the key, relative to a second member, to a second data structure that stores the second data. Based on the mapping data, the first member is allowed to access the first data and not the said second data. Based on the mapping data, the second member is allowed to access the second data and not the first data. The first data and the second data may include key values and subtrees of child keys.