@julian @mario @jupiter_rowland @benpate @fentiger @scott>Would you consider relaxing this to allow for situations (e.g. forums) where the conversation thread starter is not necessarily the manager of the container?As far as I know, in Streams OP and owner are identical, but you are right - they might as well be different. I'll mention this in the FEP.>I haven't seen collectionOf in the wild before, what purpose does it serve here?Again, this is what Streams does, I'm guessing this is because some context collections contain posts and not activities, and collectionOf tells you how to parse the collection without resorting to duck typing.I would prefer to use an outbox property for containers.