(Actually, there's one really important-to-me meta-feature of DreamWidth that can't happen until the next journaling site happens, of which this is a manifestation.)
A big thing that's important about LiveJournal is the friendspage. One page, and I can see everything my friends post, including things that they've friendslocked in ways that allow me access to read them.
Well, everything my friends post on LiveJournal. Which, up until just lately, was close enough to "everything" as to not make much difference -- but only because most everything was on LiveJournal.
Similarly, my DreamWidth friendslist will include everything friendslocked on DreamWidth, but it can't contain stuff friendslocked to my LiveJournal account. People can crosspost, but crossposting is messy and not really the right solution.
But look what happens when another journal site comes along that uses the DreamWidth code. Let's call it SleepGradient (which has a hidden meaning I'll explain in a bit). If I've got an account on SleepGradient, that gives me an OpenID, and my friends on DreamWidth can put that OpenID in their friendslist. And then SleepGradient, when I'm logged in, has all the access information it needs to go to DreamWidth and ask for posts that are friendslocked to me -- and it is a simple matter of coding for it to do that and include those posts in the friendspage that it shows me along with the SleepGradient posts. All in one page, just as if they were all part of the same overall community.
Not only is it a simple matter of coding (as opposed to a complicated matter of policy and design), but it's something that I would expect to be entirely in line with the DreamWidth vision, and something I would expect them to implement as soon as it becomes relevant.
And that makes the circle complete. With that, with a SleepGradient account, I could put people on DreamWidth in my "circle" and let them read my posts (even locked ones) and vice versa, and I could subscribe to their journals and see them in my friendspage -- even the locked posts, if they've given me access. It would no longer matter that we had accounts on separate sites.
That's the meta-feature that matters to me here. It's my hope that this exodus from LiveJournal to DreamWidth will be the last exodus that matters in this community-shuffling way for quite some time; that from DreamWidth we go into a broader cross-site journalspace where it's no longer confined to a single provider, and a friend moving from DreamWidth to SleepGradient would merely mean that I might have to update their name in my access lists, but otherwise it wouldn't affect me any more than them changing an email address would.
(And that's where the SleepGradient name comes in. Mostly it's just a riff off of DreamWidth, like a lot of the LiveJournal clone sites used. But there's a bit more, too -- see, the name of my personal website, dpdx.net, is mathematics for a pressure gradient, and "sleep" means that it's not woken up yet. So "SleepGradient" might as well refer to a hypothetical DreamWidth-codebase site that I'm running on my own computer, just for me. I really don't want to try to install and run something with this big a codebase -- but the idea that, y'know, I could if I needed to, and could still be part of the same community, is something that I think is a very big deal.)
A year ago, when the last round of serious discussons of leaving LiveJournal went around, this was what I'd envisioned as the right next step, but I had nowhere near the time to work on making it happen (save for that post). I'm really deeply pleased that I wasn't the only person with that vision, and that other people are actually making real progress towards making it happen.