[aeone]

If you're saying what I think you're saying, I think you've misunderstood: if this feature is like their current Labs offering, the "Promotions" label is applied to your incoming mail that is best classified as a "Promotion", such as any promotional email from sites you shop at - it's not additional content that Gmail is feeding you. If you don't have any such email, I suspect this category would simply be empty for you.