If you consider what marketing really can be to a company, I think marketing at its best can be finding an unmet need and satisfying they need. Even before your company has a product. Many times marketers already have a product, and their role is more of having to sell that product to customers. Through market research or a situation analysis a marketing person can discover the unmet needs of their customers.
A recent example was a company that makes funeral urns that can be x-rayed. Customers needed to take their departed through the x-ray machines at airports (your not going to send your parent in the baggage hold), a company has developed an urn that you can take through x-ray machines, the first of its kind. Apparently the product is a real hit and they are selling 300 a week.