The first cost relates to the ability to cheaply verify the attributes of a transaction. The second one to the ability to bootstrap and operate a digital marketplace without the need for a traditional intermediary. A blockchain allows a decentralized network of economic agents to agree, at regular intervals, about the true state of shared data. This shared data can sup- port multiple types of online transactions and corresponding payments, exchanges of IP, information or other types of digital assets. The resulting digital marketplaces are characterized by increased competition, lower barriers to entry, lower privacy risk, and allow participants to make join investments in shared infrastructure without assigning market power to a platform operator.