Clients, Users, and Customers: what's the difference

Client
This is the person or firm or agency that hires a designer or product design firm to develop a product. (In the 2.009 context, this would be represented by any of the presenters at the Ideas Fair. Teams may also find their own clients, even though there is no $$ exchanged.)

User
This is the person the product is designed for. It could be the primary user or anyone else that interacts with the product during it’s life cycle.  The product meets their needs. (Example, a bike commuter needing a bike helmet.)

Customer
This is the actual purchaser of the product. They may also be a user.  In the case of a toy, for example, there may be a customer, the parent, and a user, the child, but the parent will also have use needs (e.g. safety) as well.