Initial release of ForeverDB will focus on operationalizing the three categories of data it was designed to manage.
Eternal storage represents the history of change as it happened, in the language of the domain, suitable for reconstructing that history on demand. Information in Eternal Storage is guaranteed to be lossless.
Long-term storage is that subset of all historical change that constitutes the state of all relevant, active identities in the enterprise. This will be different in different domains and across organizations, and the identities managed can change over time based on the business logic of the domain, but at any point in time, it represents the sum total of known truth about active entities across the enterprise.
Short-term storage is that subset of all relevant, active identities in the enterprise whose data is needed today. Typically short term storage takes the form of a distributed cache that is read-only and therefore very fast and highly scalable.
Eventually we expect to make journals stored in Eternal Storage public for sharing across organizational boundaries through Apex BlockSync, but this will be transparent to the databases stored in ForeverDB from an operational point of view.