The recent Facebook data misadventure showed what can happen when data owners give up control of their data. If they did not give up control, then such data misuse could have been forestalled. If the data owners needed to receive assurance from credible sources that the data would be used only for specified purposes, then they could decide whether to grant the permission to use it.
Blockchain comes in two basic varieties - permissioned and permissionless. Permissionless blockchains are open to the public and any participants can join together to create a consensus on the use fo the data. Permissioned blockchain reserves control over the actions in the blockchain to approved participants. Most corporate blockchains currently being implemented are of the permissioned variety.
Facebook did not use blockchain at all, but if they had used permissioned ones, with the data owners as approved participants, then the owners of the data could have had a voice in the use of their data - they could be part of the consensus. If a particular organization approached them to use the data, then the data owners could give them a 'yes' or 'no'. Or they could say 'you can use the data that directly applies to your purpose, but you don't need the data items that do not so relate, such as people's addresses, emails, etc.' The data included in the permissioned activity, in other words, could be screened out to reduce the possibility of misuse.
Blockchain does not provide absolute assurance of proper use of data, because people are still involved. However, it would provide a powerful means of reducing the possibility of misuse. We will be seeing a growing use of blockchain or perhaps other distributed ledgers for these purposes.
For a good article on this topic, check this out.