Entia non sunt multiplicanda praeter necessitatem

In English: Entities should be multiplied beyond necessity – http://en.wikipedia.org/wiki/Occam%27s_razor

Semantic Entities should not be duplicated in the entity store: this is often happening when dereferencing is done asynchronous event listeners running un concurrent transactions. In order to avoid this the dereferenced entities should be created / updated in batch by a single thread managing it's own transaction. Asynchronous event listeners should all send the dereferenced entities to the service by using a simple queue.