We can't expect users to know #all existing groups (though there's a list) besides that we also let them their #freedom to make 1 or more parallel groups. That the current #statusnet software may be perceived as not supporting all of them (though there's a plugin for that) is for me not so a strong argument. I like more that there can be devlopped #sub-cultures by making those parallel groups AND I like this suggestion of yours: http://quitter.se/notice/2148392