These intra-diary discussion threads are getting pretty interesting. Have to contribute a bit. Kelly and lilo, I think a unified planetary government will happen, but but not while one planet is all there is.
I think it's in the human nature to need enemies, or at least adversaries. All the time small peoples have first squabbled, until communications have gotten better and their world has gotten larger, and they've seen that they're really rather alike, compared to those other folks. It takes a common enemy.
The problem is that right now, the world cannot get much larger, the global village is the only one there is. And thus it cannot really unite.
So. It won't happen until we start real extraterrestrial colonization, or get first contact. In either case, it's just a change in the scale of the us/them -dichotomy. But we can't get rid of it.
Which may prove most unfortunate in the latter case.
Btw, a bit of meta: the reason, I think, why these diaries are so successful, is that they sort of give the feeling of fighting on one's homeground. This diary page is my page, and everyone else who reads this reads this by her own explicit choice. Since I'm not forcing this down anyone's throat, I feel free to say whatsoever I bloody well want to. This is in contrast to articles and comments, since posting one of those means that you're actively trying to make other people see what you have to say, and then you have the responsibility for actually saying something worthwhile.
Moreover, though everyone is free to comment on other folks' diary pieces, they, too, can only do it passively, without any promotion except an entry in the updated diary list. I don't have to fear that some other person's comment would appear right below this diary entry and point out in excruciating detail how silly it is.
So, do not add full threading and "links to followups" to the diary entries. Making it easier to add a link to the entry you are commenting on is okay, but not vice versa! The feeling of independence and total control of one's diary page is crucial.
In fact, this is pretty similar to posting one's opinions on one's home page, except that in advogato it's easier to view lots of these together. However, I'm a bit unhappy that I have to place all this stuff I write on a foreign server. Of course I can keep a backup for myself, but it still doesn't feel the same...
Actually, perhaps finger would be a better comparison. I think that nowadays finger would be quite forgotten, had it not been for the id guys, who used to post lots of interesting stuff in their finger entries in the heyday of Quake. So even now we have sites like http://finger.planetquake.com/ which really resembles quite closely these advogato diaries, except that here we have lots more inter-diary communication.
But anyway I think it's this feeling of homeground, and passiveness, that makes the diaries so popular. Finger still beats advogato on this, though: with finger, or with your home page, you post the stuff on your own server, whereas in advogato it's a foreign server, but at least your own page.
I think this could be improved if the advogato engine could import the diary entries via finger, or via http, from people's own machines. A bit like quakefinger, perhaps. Then the passiveness of these diaries could be emphasized in that one wouldn't even have to actively post them on this advogato server, but the server would fetch them on its own.
Technically, this may not make much sense, but I think this is quite important psychologically.