Did anyone reading this initially get the impression that Less Wrong was cultish when they first discovered it?

What do you mean, "initially" ? I am still getting that impression ! For example, just count the number of times Eliezer (who appears to only have a single name, like Prince or Jesus) is mentioned in the other comments on this post. And he's usually mentioned in the context of, "As Eliezer says...", as though the mere fact that it is Eliezer who says these things was enough.

The obvious counter-argument to the above is, "I like the things Eliezer says because they make sense, not because I worship him personally", but... well... that's what one would expect a cultist to say, no ?

Less Wrongers also seem to have their own vocabulary ("taboo that term or risk becoming mind-killed, which would be un-Bayesian"). We spend a lot of time worrying about doomsday events that most people would consider science-fictional (at best). We also cultivate a vaguely menacing air of superiority, as we talk about uplifting the ignorant masses by spreading our doctrine of rationality. As far as warning signs go, we've got it covered...