The fine print: Of late, the power grid has become a target for state-sponsored hackers. Securing all that transaction data will be a complicated cybersecurity challenge.

Players: Power Ledger, Grid Singularity, Grid+, the Energy Web Foundation, the Enerchain project

Internet advertising & social media

Why you should buy in: If you could easily control your personal data and decide whether the likes of Facebook, Google, and others get to exploit it for profit, you would, right? Put it on a blockchain, which will encrypt and store your data in a decentralized network, instead of on company-owned servers. You can surf the internet anonymously, manage your own sensitive and identifying data, and control which sites can access it. Ahhhh, the internet as it was meant to be.

The fine print: Despite revelations that big tech companies are pulling all manner of shenanigans with user data, people have yet to #deletefacebook or abandon web services in large numbers. The vision of a decentralized web could be a tough sell.

Players: Blockstack, Protocol Labs

Food & Agriculture

Why you should buy in: How do you know if that meat you bought is really grass-fed, organic, and free of antibiotics and has never been anywhere near a cage or feedlot? You don’t—unless a blockchain tells you so. Having a digital ledger that no one can mess with means everything from turkeys to chocolate to mangoes can be tracked literally from farm to table—or at least to the grocery store shelf. And if something does go wrong, a blockchain can cut the time it takes to track, and stop, the spread of a foodborne illness.

The fine print: A few pilot projects have been tried, but that’s it so far. A large-scale system would probably mean giving farmers, distributors, and others keys to access and modify the blockchain, and we’d have to trust that they wouldn’t misuse them.

Players: IBM, Walmart, Nestlé, Unilever, Cargill

Medicine

Why you should buy in: Sharing x-rays, blood test results, and other intensely private medical data is no easy task, and there are piles of regulations, differing data formats, and other hurdles to contend with besides. A blockchain could provide a tamper-proof record of important events like prescription refills, while smart contracts could give patients precise control over who can access which parts of their medical record and when, without all the red tape.

The fine print: Hospitals, clinics, doctor’s offices, pharmacies, insurers … the list of who may need access to your medical records is long. Who should be allowed to change the record? Who will run the computer network that runs the blockchain? How will the system be governed?

Players: MIT’s MedRec project, Massachusetts General Hospital, Kaiser Permanente, IBM, the Mediledger Project, SimplyVital Health