The key is that HP&TMoR is read in "fun time", while I believe most people see LW time as "work towards self-improvement" time. Ironic, but true for me and the friends I've polled, at least)

Why I read less wrong:

• A. 23% Already read all the good web-comics today
• B. 22% To discuss important ideas that aren't being discussed anywhere else, eg friendly AI
• C. 20% To show off, gain some name recognition, and meet interesting people
• D. 19% To cooperate with others in analyzing rationality, behavior, ethics, and the future in a more rigorous way than is being done elsewhere
• E. 10% To observe arguments between smart people, and get a sense for how smartness correlates with agreement, making stupid errors, and size and frequency of blind spots; or how it generalizes across domains
• F. 6% Self-improvement

Item D is the most important to me, but LessWrong has not been very successful at it. EY rarely gives the posts that I think are important along those lines the coveted green button, nor does the LW readership vote them up highly.

I think that the most important purpose LW could serve would be to critically analyze the ideas EY has put forth, and discuss different possible paths to a better future. But, AFAIK, EY has not given the green button to any posts that look at his ideas critically. Most readers never see posts that don't get the green button. So LW doesn't serve that purpose well.

Self-improvement for me from LW does not usually come from the akrasia stuff. pjeby's website is more interesting for that, at least what I've looked at so far. (I read "Everything I Needed To Know About Life, I Learned From Supervillains" yesterday, and recommend it.) It comes more in finding specific errors in my reasoning or holes in my understanding, and calibrating.

EY's sequences and early posts are very different from the usual self-improvement stuff. I think people would benefit more from reading the sequences than from staying current on all the new posts (yet I do the latter instead of the former). I know people aren't reading them, because he has some good posts (old ones, backdated to before LW existed; maybe they were imported from OB) with only a couple of upvotes.