Considering the amount of the personal data still going through email, this is one of the few areas that no one should be giving up to any third party services,

Considering the amount of the personal data still going through email, this is one of the few areas that no one should be giving up to any third party services, regardless of the benefits it may provide. Encryption with you owning the key is a requirement if it is going to be stored on a third party service. You can provide a subscription model for the server costs if need be.