Rebates conditional on positive reviews are a practice in which sellers offer purchasing consumers rebates redeemable only if the consumers post positive reviews online. This conditional-rebate strategy is different from the typical unconditional-rebate strategy and becomes controversial because in some sense sellers bribe buyers for positive reviews rather than simply expanding the review pool using monetary incentives. A typical conditional-rebate strategy on Taobao.com works as follows.<ref name="Chen-etal" /> When a buyer places an online order with a seller, the buyer is unaware of the existence or the amount of the rebate. When shipping the product, the seller might include a mail-in conditional rebate. The key conditions to redeem the rebate include leaving a five-star rating and writing reviews that meet some minimum length requirement. The distinctive feature of this type of rebate is that only those purchasing consumers who post positive reviews are eligible to redeem rebates. Once done, the consumer needs to take a screenshot or photo of the review and send it to the seller for verification. Afterwards, the rebate is honored by the seller through Alipay (a widely adopted mobile payment method and e-wallet).