Private label SEO is simply another name for white labeled SEO. They are the same thing. White / Private can basically be interchangeable. They both mean that the delivery organization in the partnership is not visible to the end-client. The group that does the work is behind the scenes entirely from the paying customer. The group that does the sales, also known as the reseller, is usually responsible for customer service in a private label SEO arrangement. There are many examples in the large corporate world of private label reseller arrangements. SEO is no different from these other examples.