I suspect it's still out there on Tumblr and such, but I miss the days of journals and comms, where I could find things and interact with them (and, if I was the one posting, could control who saw it).

Exactly. I want to be able to interact in a way you really can't on twitter.

when the fan community really is one - people whom you know, and have interacted with before, and have a sense of shared interests with. It doesn't surprise me that it's in short supply when "fandom" is so much more widespread and so impermanent; there's a difference between a fan community and a Twitter hashtag, and that difference seems like it's related to the level of conflict 'fandom' now frequently entails.

That's a really good point. Though even back in the day, there could be a lot of explosive drama. But not on the same level, I don't think.