I remember Eliezer's post announcing LW. He didn't give any explanation of why it was called that, he just said "tentatively titled Less Wrong."
I'd be interested in hearing the answer to this. I suspect it was just a cool name that Eliezer came up with.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
(I plan to make these threads from now on. Downvote if you disapprove. If I miss one, feel free to do it yourself.)