@david I've already read it. We're talking about conversations, where you normally want to see/hear what other participants are saying (and for them to see/hear what you're saying). Compare it to talking with your real-life friends. A friend of one of your friends may join your conversation. You are still able to hear what the person says, even though he/she is not (yet) your direct friend. That's missing in !sn / !gnusocial conversations right now, and it annoys people enough to abandon smaller instances.