This lecture covers the concept of eventual consistency, contrasting strong and weak consistency models with eventual consistency, which guarantees that all reads return the last written value after no more updates. It delves into the implementation of an eventually consistent store using actors in Scala, discussing the dissemination of updates and the importance of employing suitable data structures like CRDTs for achieving eventual consistency. An example data structure, the cluster membership state, is presented as a convergent data type with conflict resolution and commutativity properties.