Co-presence data retrieval system which indicates observers of data

A data retrieval system has a data server, a co-presence server and at least one awareness co-presence client. The data server retrieves at least one data object from among a plurality of data objects stored in a data repository. The co-presence server opens communication and observation channels associated with at least one of the data objects. The awareness co-presence clients communicate with the co-presence server and define an awareness state of the client. The co-presence server opens a communication channel or an observation channel with each client depending on the awareness state of each client per retrieved data object. For observation channels, the co-presence server indicates to each client which other clients have retrieved the same data object. The co-presence server opens a communication channel associated with a retrieved data object to those clients which retrieved the data object and which are in a communication type of awareness state.