Distributed Databases

For a long time I've been interested in the idea of a distributed database. While it would be hard to do, one way that would make it easier is to for the local sites that were part of the decentralized database network to store the data in two parts. The first part would be data that came from that location and could be edited. The second part would be global data that would be updated based on a regular time schedule. Thus things could only be edited/deleted in one spot. Updating the local read-only database would still be messy.