Realistically, when someone replies to one of my posts on some long thread, I don't take the time to click through their handle and find their own intro post. I don't think that doing so is a good use of my time, and I believe that I am typical in this regard. However, I do take the time to read their handle, and if it seems to say "I am not arguing in good faith", I take notice.

This gives me an idea for a new Less Wrong feature, though: allow users to enter a short descriptions of themselves, and display it when the mouse hovers over their handle for a certain amount of time. I know how I'd implement it with jQuery, but I'm not sure how easy it would be to plug into the LW general architecture.