A server system, the server system being accessible to a first and a second party (103a, 103b) from their respective user terminals via a network, the server system comprising: a respective storage area for each of a plurality of respective parties including the first party and the second party, wherein the respective storage area of the first party stores a primary instance of a data resource of the first party, the primary instance including common metadata of the data resource and personal metadata of the first party describing one or more attributes of a relationship between the first party and the data resource; and a manager function configured to perform operations of: in response to the second party forming a relationship with the data resource of the first party, establishing a secondary copy of the primary instance in the respective storage area of the second party, wherein the storage area of the first party and the storage area of the second party are implemented on a physically separate respective region of memory, wherein: the secondary copy includes only the common metadata of the data resource and personal metadata of the second party specific to the secondary copy, the personal metadata of the second party describing one or more attributes of the relationship between the second party and the data resource; and in response to detecting a modification of the primary instance that includes a change to the common metadata of the data resource and the personal metadata of the first party, propagating the modification of the primary instance including the change to the common metadata to the secondary copy without propagating the change to the personal metadata of the first party. a respective storage area for each of a plurality of respective parties including the first party and the second party, wherein the respective storage area of the first party stores a primary instance of a data resource of the first party, the primary instance including common metadata of the data resource and personal metadata of the first party describing one or more attributes of a relationship between the first party and the data resource; and a manager function configured to perform operations of: in response to the second party forming a relationship with the data resource of the first party, establishing a secondary copy of the primary instance in the respective storage area of the second party, wherein the storage area of the first party and the storage area of the second party are implemented on a physically separate respective region of memory, wherein: the secondary copy includes only the common metadata of the data resource and personal metadata of the second party specific to the secondary copy, the personal metadata of the second party describing one or more attributes of the relationship between the second party and the data resource; and in response to detecting a modification of the primary instance that includes a change to the common metadata of the data resource and the personal metadata of the first party, propagating the modification of the primary instance including the change to the common metadata to the secondary copy without propagating the change to the personal metadata of the first party. in response to the second party forming a relationship with the data resource of the first party, establishing a secondary copy of the primary instance in the respective storage area of the second party, wherein the storage area of the first party and the storage area of the second party are implemented on a physically separate respective region of memory, wherein: the secondary copy includes only the common metadata of the data resource and personal metadata of the second party specific to the secondary copy, the personal metadata of the second party describing one or more attributes of the relationship between the second party and the data resource; and in response to detecting a modification of the primary instance that includes a change to the common metadata of the data resource and the personal metadata of the first party, propagating the modification of the primary instance including the change to the common metadata to the secondary copy without propagating the change to the personal metadata of the first party.