One memetic virulence strategy operates by making outlandish promises that subscribing to it will make you smarter, richer, more successful, more attractive to the opposite sex, and just plain superior to other people - and then doing it in a way that can't obviously be proven wrong.

That similarity is the key to both the perceived creepiness factor and the signal:noise ratio on this site. Groups formed to provide a service have performance standards that their members must achieve and maintain: drama clubs and sports teams have tryouts, jobs have interviews, schools have GPA requirements, etc. By contrast, groups serving as vehicles for contagious memes avoid standards. Every believer, even if personally useless to the stated aims of the group, is a potential transmission vector.

I see two reasons to care which of those classes of groups LW more closely resembles: first, to be aware of how we're coming across to others; and second, as a measure of whether anything is actually being accomplished here.

Personally, I try to avoid packaging LW's community and content into an indivisible bundle. From Resist the Happy Death Spiral:

To summarize, you do avoid a Happy Death Spiral by (1) splitting the Great Idea into parts (2) treating every additional detail as burdensome (3) thinking about the specifics of the causal chain instead of the good or bad feelings (4) not rehearsing evidence (5) not adding happiness from claims that "you can't prove are wrong"; but not by (6) refusing to admire anything too much (7) conducting a biased search for negative points until you feel unhappy again (8) forcibly shoving an idea into a safe box.

There are a great many insightful posts on LW, mostly from Eliezer, Yvain, and a few others. There are other posts that are less specific and of correspondingly smaller insight. There is also a community centered in the discussion section that spends most of its time espousing the beliefs in the main post. Rather than allowing all these ideas to prop each other up, I'm content to wield the supported and useful techniques and discard the rest.