I think we really need a messaging app that is anonymous and don't store data on a central database but stores the data of all users on the blockchain.
Some people might begin to say that steemit already has this feature, but I can't vouch for steemit on this because of the kind of platform it has, steemit of all things is not user friendly which is a very great drawback to the steemit community, people are not just looking for ways they can make money, but people are also looking for ways to make it easily.