1. Apparatus for formatting data change requests in a peer-to-peer, activity-based collaboration system having at least two collaborating computers, each with a local copy of data thereon and wherein the collaborating computers exchange data change requests during a collaboration session for effecting changes to the local copies of data for collaborative activities, the apparatus comprising: a memory; a processor; data change request priority logic for inserting into each data change request priority information that determines an order of execution of data change requests; and dependency collision resolution logic for inserting into selected data change requests dependency information for resolving a dependency collision between first and second data change requests which both depend for execution on a third data change request wherein each of the collaborating computers and a user of that collaborating computer are an endpoint and wherein the dependency information comprises, for a data change request: an identification of data to which the data change request pertains; endpoint information identifying an endpoint from which the data change request was generated; a data change request sequence number for the data change request; and information identifying an endpoint and a data change request sequence number for a prior data change request on which the data change request depends.