dansup, but how are you going to intersect two collections that are on different instances? If, for example, you're in a group on my instance, then my instance has a complete list of group members and partial list of your friends/followers, while yours has it the other way around. Don't you need both lists fully available somewhere to intersect them so your instance could show you your friends that are in my group? BTW that's why I'm sending Add{Group} and Add{Person} to followers — it helps consistency in this particular case, and also so I could show these events in the feed.