This is how you get started with Signavio's discussion functionality: Select the process model in the Signavio Process Editor and click on the "Discuss"-button. A read-only view on the model will open up and you can add comments to individual diagram elements or the diagram as a whole. All comments are displayed and you can keep track of who said what about what revision of the model.

Just go ahead and try it! You will see that also those people who normally hate to use modeling tools will enjoy contributing their ideas.

You haven't registered for the Signavio Process Editor yet? Then please browse to Invite your colleagues to your workspace and discuss your processes.