A Project Instigator is anyone in charge of a project. Project Instigators lead the project and have the ability to edit the project profile, add project members, etc. There can be multiple Project Instigators on a single project.
Project Team members actively contribute to a project, but do not manage it at large. Project Team members could be informal technical advisors, paid employees, volunteers, or enthusiastic supporters - as approved by the Project Instigator(s).