A system for providing indications of documents currently opened by members of a group, in which document open and close operations are detected, and conveyed to a server system. The server system receives the document operation messages, and uses them to maintain lists of open documents associated with individual users through records in a user database that also indicate individual users' on-line status. When the server system transmits the on-line status of a user to other users that have an interest in that user (e.g. fellow members of a collaboration team, development project or the like, or user's having entered that user in their buddy list, etc.), an open documents list for that user is included in the message along with his or her on-line status information. The client systems maintain lists of currently accessing users for open documents they have received identifiers of within open documents lists contained in such on-line status messages. As a result, a user can select a user interface view, such as a file directory or other type of interface providing indications of multiple shared documents, and the disclosed system allows the user to quickly determine which documents are currently open by other users in a group.