How would you explain blockchain to Marketing people?

To be more specific: – How would you define the Blockchain technology (especially Ethereum) to a non-technical person? A person working in Marketing field? – How would explain the potential of this technology for the end-user? – How would you deal with their concerns (most people are concerned about the fact that blockchain has no central point of control, then it could be the far west where every sin could and will happen)?

Thanks!