1. A method of storing content for optimized delivery, the method comprising: storing content including a plurality of non-optional content items and a plurality optional selectable content items, the plurality of optional selectable content items having particular performance demands; and organizing the plurality of optional selectable content items to create a mapping of the plurality of optional selectable content items to performance capabilities associated with client devices, the mapping enabling formation of delivery content to deliver to the client devices, where the delivery content includes the non-optional content items and at least a subset of the optional selectable content, the subset of the optional selectable content being selected for delivery based on the mapping of the plurality of optional selectable content items to the performance capabilities associated with the client devices.