Abstract: In a social networking system environment, users can give another user credits, a scarce commodity, as part of commenting on content posted by the other user. These credits can be used as a peer-to-peer recommendation signal, and they can also be used as input to a decision engine that determines what content to display in a highlights section that will be viewed by a wider audience and increasing the likelihood of further engagement with the content. Credits in a social networking system environment have scarcity value. In various embodiments, in order to increase the number of credits in the system, users buy them or an administrator distributes them. In some implementations, the total amount of credits in the system can decrease if a user cashes out the credits for real money. In some implementations, credits can be used to buy virtual or real-world gifts.