Funny you mention Hacker News, I'm about 100 karma points from being in the top 100 there (though under a different name).
I suspect there's a pretty big overlap between the LW and HN crowds. I wonder if there's a high correlation between karma on one site and karma on the other?
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.