What's interesting about that is that AO3, at least, is supposed to primarily be an archive and it's had some social features bolted on, but I'm pretty sure the original idea was for you to post there so there was always a copy that could be referenced and most of the social interaction was supposed to happen elsewhere. But with the collapse of LiveJournal an good the fragmented chaotic mess that succeeded it, AO3's social became something with clout by virtue of volume of works. In theory, we're all supposed to already have our text websites where most of the interaction happens and the AO3 copy is there in case our sites vanish. I know we'll never get back to the way Web 1.0 did things, but I feel like that's the general direction most of fandom is pulling for, since they're old enough to remember it.