Decentralized ad network (attention marketplace) where user set the price they are willing to "sell" their attention using Nostr relays  

 https://1.bp.blogspot.com/-5FR2cchV2N4/XUrr9e6V5ZI/AAAAAAAAf0E/4vH_p6Up0HgAZctCqX5-mQ82XtbkN6a8QCLcBGAs/s640/brain%2Bdown.gif