So, we have three introduction threads, and recently have had several contentious ones, like AspiringKnitter's introduction as a theist or Bakkot's introduction as a proponent of infanticide. It seems to me like there's value in trying to come up with a unified policy on how to respond to introductions. Replies seem to run the emotional gamut, and different norms often conflict. Beyond that, practical concerns suggest arguments may be poorly suited to introduction threads.
Take MagnetoHydroDynamics's introduction as not interested in cryonics as an example of a smaller discussion that spawned meta-discussions about attitudes. Epistemic hygiene suggests that challenging wrong beliefs is a positive, but I found myself dismayed to find the only reply to a newbie's first post was a factual correction, and so posted a welcoming comment with a joke. Later, wedrifid posed a test for MHD, which MHD passed. Kaj_Sotala questioned wedrifid's tone on the grounds that MHD was a newcomer, and I'm not entirely sure what to think. On the one hand, I can easily come up with a friendly rewriting on wedrifid's test, and I think friendliness to newcomers is a sound strategy. But on the other hand, while testing newcomers can turn some away, it does so in a selective way. Should newcomers be shielded from some criticism in introduction threads, or should it be the same as the rest of LW? Are there inappropriate attitudes in introduction threads?
The practical concern is that pages only display 500 comments at once, which is why we have three threads now. But on the first day of 2012, our 2012 thread already has over half the comments it'll be able to display simultaneously. (The post has been up for a week, not a day, but still.) At time of writing, 150 of the 270 comments are children of Bakkot's comment, arguing about infanticide. It seems obvious to me that we ought to seriously discourage promoting discussion on ideas in introduction threads, and instead point people to open threads / a primer on writing discussion posts.