Taobao's advertisement is that the seller has opened a through train, and this position belongs to the seller with high bid. It is a paid through train promotion bit, which has nothing to do with the default sorting of baby. Commodity advertising is also a way to promote yourself. The purpose is to publicize this product to let more people know and let more people know and understand it. When you click in, it is the product they are selling. Every time a person clicks into the store, the merchant will pay the corresponding advertising fee to Taobao.