LW is pretty much the only site I visit where I feel significantly intimidated about commenting. I've left a couple of comments, but I seem to be more self-conscious about exposing my ignorance here than I am elsewhere – probably because I know that the chances of such ignorance being noticed are higher. It occurs to me that this is completely backwards and ridiculous, but there you have it.
Some research says that lurkers make up over 90% of online groups. I suspect that Less Wrong has an even higher percentage of lurkers than other online communities.
Please post a comment in this thread saying "Hi." You can say more if you want, but just posting "Hi" is good for a guaranteed free point of karma.
Also see the introduction thread.