I see two primary roles and their (initial) uses.
Client
Vendor
The client (or project manager/owner) will be able to define project requirements and form the necessary team elements, manage team logistics including reports and payments, and interact; the vendor (which includes designers, developers, and other working members of a team) will be able to join project teams they’ve been invited to, submit reports, interact, and make use of tools for distributed development and team integration.
The client may choose to request a manager, to be assigned by us, and whose responsibility it will be for procurement and integration of all necessary team elements.
In short, the client will be able to execute and successfully complete the project, and the vendor(s) will be able to successfully perform a service and get paid for it, with manager oversight as necessary.