Datareum is a decentralized marketplace that will enable individuals to monetize their personal data, selling it directly to market researchers, academic researchers, and other interested parties. Built on the Ethereum public blockchain, Datareum's platform will facilitate this peer-to-peer transaction of sensitive personal information securely, without the risk of hacking. Using online surveys as a starting point for building the marketplace, Datareum will employ incentive mechanisms that, over the long-term, will ensure the availability of superior quality custom data, providing an indispensable tool for researchers of all kinds.