One thing I would have preferred is a discussion of the positive externalities of signaling, not just the negative ones. For example, if Yvain and lukeprog are both trying to signal their superior intelligence by writing insightful posts, this may get into an "arms race" for them, losing utility. However, the Lesswrong community gains utility overall. I think the externalities of signaling are generally positive in the real world, they only tend to be negative in what are anyway zero-sum games (e.g. begging).

You have just summarized "civilisation" in a nutshell.