Decentralized (to me) implies a lot of people working together on something, without a clear leader or headquarters. I think he was right to use 'fragmentation' ... a lot of the conversation is isolated and most likely redundant.
To use the obligatory p2p reference... the DHT peers in bittorrent are decentralized (no clear leader but all generally working together). Private trading groups on IRC are fragmented (they are isolated from each other).
I use the word fragmentation because that's how a lot of other people are describing it. Also, decentralized already means a lot of things to other people.
What happens if we extend this notion beyond online conversations?
Does it lead to gated communities? The segregated townships in South Africa? Ignoring people because they're not part of your fragment? To the extent that we make people into "others" we reduce their humanity. And it might be that full populated fragments would reduce any tendency you'd have towards reaching out and making an "other" someone in your fragment.
There was a meme some time back about the way that cable TV changed the nature of water-cooler conversations because no one watched the same stuff anymore. I'd argue it is even worse now, because you can hop over to TelevisionWithoutPity and have a substantive conversation with people that DO care about the retcon in the 8th season of Buffy. And you'll still have nothing to talk about at work.
Do we want things reduced to limiting possible cultural touchstones to sporting events?
I think users should create their own communities by picking the set of people whose posts they would like to see. These people may not be friends.
For example, for a discussion on startups, I might specify that I would like to see PG's posts along with any posts that PG would like to see.
One could also provide exceptions. I could for example exclude certain people from the set above as well as posts from people that they receive (though not excluding someone for which there's an acceptable path to that person).
Of course, such a scheme has problems since you may reply to someone's posts yet you are not included in the set of people whose posts he/she will see.
But maybe one can find a way to make this workable.
It works great if you pick the set of people whose threads you would like to see. That way encourages discoverability since you see your 'followee's posts but also other people on those threads that you may find you're interested in.
This is the approach I took with my hystry interface for HN. I have whitelists and blacklists, and show threads involving people on the whitelist but not comments by people on the blacklist.
http://news.ycombinator.com/item?id=71827
One other advantage of fragmentation (which I'm surprised he did not touch) that became apparent as I've been trying ffeed is that I am free to say stuff relevant to me as opposed to a public forum with people who do not know me.
I think a good unified commenting system that allowed for friending would be an alternative.
If comments from my friends boiled to the top of Disqus, it would be the best of both worlds. For Tipjoy, I had been thinking that using Disqus could be useful for comments if we could feed to and from the original thread on a blog.
So commenters could tip the blog poster for useful content, and likewise the poster could tip commenters to reward intriguing comments. Commenters could tip fellow commenters. Lurker nonmembers could tip everbody.
I bet someday somebody comes up with a formula that describes the optimal amount of fragmentation for any given community.
I would think that there must exist some sort of rational percentage of fragmentation that is beneficial to prevent stagnation, but above which creates a less than optimal signal-to-noise ratio and leads to a steady decline in the percentage of useful or substantive interaction.
Hmm, I can only hope whoever it is names it "Trevor's Law" :-P
His argument could apply equally well to explain that the fragmentation (read: number of) Linux distributions is not such a bad thing either. It is just a sign people have freedom to do what they want, and guess what, when people have freedom, they will not always all do the same thing as everyone else.
