I strongly believe that Blockchain Technology can help guaranty the privacy of data stored on the cloud.
Currently, there are different services that provide storage for individuals and companies to their files on the cloud, this includes Google Drive, DropBox etc. The files stored on these platforms leave in facilities provided and managed by the Companies that run them. Though, this companies promise that the privacy of your files and data is guaranteed, with the right incentive, they can still tamper with the files stored on their servers if they want to.
This means that the users of these platforms need to continue to hope that the wrong people with the incentive to tamper with their data stored by these companies never get into the position to do that. They are not in control of their data neither are they in control of the people managing it.