I think the "no registration required" message that every new visitor sees on the front page is a bit misleading.
… or isn't it?
Obviously, you have to register somehow to get started and I assume that most new users start asking questions rather than answering them – otherwise we wouldn't have this policy of registration at all.
I'd leave it up for the team to decide on a more appropriate message.
And yes, I know that you can answer questions without signing up.