Today's post, Every Cause Wants To Be A Cult was originally published on 12 December 2007. A summary (taken from the LW wiki):

Simply having a good idea at the center of a group of people is not enough to prevent that group from becoming a cult. As long as the idea's adherents are human, they will be vulnerable to the flaws in reasoning that cause cults. Simply basing a group around the idea of being rational is not enough. You have to actually put in the work to oppose the slide into cultishness.

Discuss the post here (rather than in the comments to the original post).

This post is part of the Rerunning the Sequences series, where we'll be going through Eliezer Yudkowsky's old posts in order so that people who are interested can (re-)read and discuss them. The previous post was The Robbers Cave Experiment, and you can use the sequence_reruns tag or rss feed to follow the rest of the series.

Sequence reruns are a community-driven effort. You can participate by re-reading the sequence post, discussing it here, posting the next day's sequence reruns post, or summarizing forthcoming articles on the wiki. Go here for more details, or to have meta discussions about the Rerunning the Sequences series.