Very often, they will not only identify your site's problems but offer solutions you might never have thought of. In using the results of user tests or interviews to help you define problems, make sure to look for patterns. It's easy to get bogged down in small differences of opinion. Step back and look at the big picture. If you understand how problems are interrelated, you can work toward much more cohesive and effective solutions.
Most people assume that total freedom is required for creativity.
Imagine that you work for a beverage company. Brainstorm a new product. Now imagine that you work for a car company. Brainstorm a new product that will appeal to teenagers who have just received a driver's license. It should also appeal to parents who might purchase this product for their son or daughter.