I do disagree with your assessment that LW has made very little progress. As Luke pointed out below, we frequently have new work being done, and references to work being done by other people. I suspect the source of this feeling is that nearly all of the progress lies within a very small field. This blog is a mix of human rationality (specifically, improving the way we think), and Artificial Intelligence.
If you are like me (and I have a slight suspicion that you do fit into this category), you don't actually pay that much attention to the discussions of Artificial Intelligence. I really don't particularly care that we've found a slightly better way to make computers perform Solomonoff Induction. It isn't part of the fields I work in, and to actually understand it, I would have to study AI to a much greater depth than appears useful to me.
In lukeprog's list, if I'm being as generous as I can about which of the two categories the topics fall in, I wind up with 8 posts on rationality and 8 on Artificial Intelligence. (I did count things like learning to program as rationality, even though they're edge cases). I do think it's worth noting that the amount of rationality material in the "intellectual productivity" section is less than 1/2.
So, if you aren't really paying that much attention to the AI posts, that means that about half the posts in the last two weeks haven't been of much value to you. Then we have to consider that not all of the "rationality" material is particularly interesting to you.
And so we wind up with a blog where the only people to whom a large fraction of the posts on this website are particularly relevant are people working in or with a strong interest in Artificial Intelligence. Which is a bit of a shame, since that's probably nowhere near all of the rationalists in the world.
Guys I'd like your opinion on something.
Do you think LessWrong is too intellectually insular? What I mean by this is that we very seldom seem to adopt useful vocabulary or arguments or information from outside of LessWrong. For example all I can think of is some of Robin Hanson's and Paul Graham's stuff. But I don't think Robin Hanson really counts as Overcoming Bias used to be LessWrong.
Edit: Apparently this has been a source of much confusion and mistargeted replies. While I wouldn't mind even more references to quality outside writing, this wasn't my concern. I'm surprised this was problematic to understand for two reasons. First I gave examples of two thinker that aren't often linked to by recent articles on LW yet have clearly greatly influenced us. Secondly this is a trivially false interpretation, as my own submission history shows (it is littered with well received outside links). I think this arises because when I wrote "we seem to not update on ideas and concepts that didn't originate here" people read it as "we don't link to ideas and concepts" or maybe "we don't talk about ideas and concepts" from outside. I clarified this several times in the comments, most extensively here. Yet it doesn't seem to have made much of an impact. Maybe it will be easier to understand if I put it this way, interesting material from the outside never seems to get added to something like the sequences or the wiki. The sole exception to this is hunting even more academic references for the conclusions and concepts we already know and embrace. Thus while individuals will update on them and perhaps even reference them in the future the community as a whole will not. They don't become part of the expected background knowledge when discussing certain topics. Over time their impact thus fades in a way the old core material doesn't.The community seems to not update on ideas and concepts that didn't originate here. The only major examples fellow LWers brought up in conversation where works that Eliezer cited as great or influential. :/
Another thing, I could be wrong about this naturally, but it seems to clear that LessWrong has not grown. I'm not talking numerically. I can't put my finger to major progress done in the past 2 years. I have heard several other users express similar sentiments. To quote one user:
I've recently come to think this is probably true to the first approximation. I was checking out a blogroll and saw LessWrong listed as Eliezer's blog about rationality. I realized that essentially it is. And worse this makes it a very crappy blog since the author doesn't make new updates any more. Originally the man had high hopes for the site. He wanted to build something that could keep going on its own, growing without him. It turned out to be a community mostly dedicated to studying the scrolls he left behind. We don't even seem to do a good job of getting others to read the scrolls.
Overall there seems to be little enthusiasm for actually systematically reading the old material. I'm going to share my take on what is I think a symptom of this. I was debating which title to pick for my first ever original content Main article (it was originally titled "On Conspiracy Theories") and made what at first felt like a joke but then took on a horrible ring of:
We like linking articles, and while people may read a link the first time, they don't tend to read it the second or third time they run across it. The phrase is eventually picked up and used out the appropriate of context. Something that was supposed to be shorthand for a nuanced argument starts to mean exactly what "it says". Well not exactly, people still recall it is a vague applause light. Which is actually worse.
I cited precisely "Politics is the Mindkiller" as an example of this. In the original article Eliezer basically argues that gratuitous politics, political thinking that isn't outweighed by its value to the art of rationality, is to be avoided. This soon came to meant it is forbidden to discuss politics in Main and Discussion articles, though it does live in the comment sections.
Now the question if LessWrong remains productive intellectually, is separate from the question of it being insular. But I feel both need to be discussed. If our community wasn't growing and it wasn't insular either, it could at least remain relevant.
This site has a wonderful ethos for discussion and thought. Why do we seem to be wasting it?