In the microblog model, Francis posts a message and it goes to all his followers. Taylor responds and the response goes to all her followers. Taylor's response is rarely seen by the rest of Francis's followers. They are different conversations with completely different audiences.In the conversation model, Francis posts a message to all his followers. Taylor responds (only) to Francis, and Francis relays the comments to all his followers.In this way, Francis has a contained conversation. There is one audience and one set of messages that are part of the conversation. Francis owns this conversation and decides who is a part of it. Taylor's followers aren't involved in any way.This type of construct is a requirement for providing private groups and circles/aspects in the fediverse - as these features are by definition "contained conversations". It mostly provides a range of interactions that can't really be provided by the microblog model.
