Important question saurik! Our primary store is mongo. All data is replicated in different availability zones and at least one additional replica which is kept in a different ec2 region. A running snapshot backup is also taken at least every 30 minutes. Simperium isn't a messaging service. Every change is persisted and versioned. So for the Simplesmash demo, you could have a slider that would allow you to go back in time and replay movements. A note on versions: they are stored in an RRD like fashion. At first every version is kept, and as they accumulate; older versions are compacted and become less granular. We plan on making what level of granularity is kept an adjustable option in the future.