Davy really nicely introduced the problem of looking at a snapshot of a data base. This problem obviously exists for any data base technology. You have a lot of timestamped records but running a query as if you fired it a couple of month ago is always a difficult challange.
With FluxGraph a solution to this is introduced.
How I understood him in the talk he introduces new versions of a vertex or an edge everytime it gets updated, added or removed. So far I am wondering about scaling and runtime. This approach seems like a lot of overhead to me. Later during Q & A I began to have the feeling that he has a more efficient way of storing this information so I really have to get in touch with davy to rediscuss the internals.
FluxGraph anyway provides a very clean API to access these temporal information.
On the various snapshots of the graph one is able to calculate for example the difference graph of the two checkpoints and gets  a fully blueprints compatible result graph.
github.com/datablend/fluxgraph
His use case comes from a data set with 15000 cancer patients from 2001 to 2010 on which he could ask questions.
As a resume I can say that Davy used his software for his work and open sourced it which is cool.