A collaboration server hosts software for collaborative composition and editing of a media project with project collaborators using different media editing applications each having their own native data format. Project collaborators, such as video editors, sound editors, effects and graphics artists, and producers access a shared project workspace which contains a snapshot of the current state of the media project in a canonical format, as well as source media files, native application metadata, and change notes. Each editing application includes a module enabling it to read the canonical snapshot representation, and also to flatten its native data model representation into the canonical representation for writing to the shared project workspace. A collaboration server hosts the shared project space, and includes a workflow manager for issuing change notifications and handling versions, and an application server for the shared project user interface. Change notes are generated manually and also expressed automatically in terms of machine-readable change primitives that serve to direct an editor's attention to portions of the media project needing attention.