At the very least, a hint (or a “seed” might also be an appropriate term) is a useful way of providing a context from which to generate discussion and ideas. The use of hints could also be expanded to integrate multiple facets into a brainstorming exercise. The hint might be incidental (contact in an unintended manner) or purposeful (part of an agenda).
The Incidental Hint: this is more likely the case for teaching moments where spontaneous and freeform brainstorming is desired, and there is freedom to explore. We might just gather a group together, state an unexpected topic (and objective) and let everyone interact. An incidental hint, for example, might come from listening to the radio or reading a magazine.
The Purposeful Hint: in a research or business setting, there is probably a framework from which one would select a hint. For example, in order for a company to design a new product, it would be useful to know what current technologies are available (mobile devices, eg), or what the customers are asking for (pharmaceuticals, eg).
The hint contributes greater definition to an idea and is tied to a scope. A series of concurrently developed products with similar hints might constitute a product family.