Find your niche
HBS via CNet has an article on strategies for niche players in larger business ecosystems, such as those surrounding Walmart and Microsoft. The basic advice is commonsensical: find a specialty where you can create value, leverage the value of the platform but avoid being overly dependent on the big fish. The analogy of loosely coupled software architecture is a good one. Design your business to be able to get value from other entities, but don't bind yourself to them too closely. Your interests may be aligned, but they are not the same.