I'm having a few thoughts on social norms. I'm used to IRC and Usenet, where a channel or group is understood to be an open forum and, when people make a statement, it is seen as normal for anyone else, acquainted or not, to respond to it, even tangentially.
But on more social-network-style graph-based communications where the flow is determined by a follow edge between nodes or something like it, a lot of people find it disturbing or invasive to have strangers pop into their mentions to rebut, add, or jump off from their point.
I think this causes a lot of friction and expectation mismatches. I don't think either norm is wrong, though it is useful if people make it clear which one they're expecting.
For the avoidance of doubt, I'm an IRC-type person. If I'm posting public or unlisted, I do not mind strangers to disagree with me, add their own twist, or give their own reaction. I will also respect the desire of graph people who don't want me to do that to them.
#fediculture @irc #cyber #SocialNetworking