While you can create your own Shared Parameters in the Manage tab and you can add them to your project such that they show up in the properties, there doesn't seem to be a way to make them populate their assigned value in a sheet. I would like to be able to create a shared parameter, add that parameter to my project as an instance or type parameter under the assemblies category, create a label for it within a title block, insert the title block on a sheet, and have that parameters value (text or integer) populate that label in a sheet for a specific assembly.
I have been told this is not possible in Revit currently.