This is a first pass at building a use case model for real estate project management. As you can see on the left side of the system, there are five actors: the project manager, salesperson, administrative assistant, buyer, and the seller. On the right side of the model are three external systems which interface with the model. They are Google Wave, SalesForce, and OpenProj.
The system's use cases are self-explanatory and may need refactoring. Again, this is a first pass. In addition, I'm sure more use cases will rear their heads so I expect the number of use cases to grow.
Feel free to leave comments and suggestions for this model is open for public comment.