I have to preface this whole post by saying it is generated by curiosity, and I intend nothing other than positive communication from it!
Why do some people have their comments moderated (so they don't appear until approved) and still require those dreaded captcha boxes (where you have to try and decipher and enter letters before it will even accept the comment)? It seems redundant to me. If you're going to moderate it anyway, who cares if it's legitimate before that?
Now that I've said that, I hope mine is set up to only moderate (if not, let me know!). Every comment that is left for me, I receive a notice in my email and go in to choose to accept or reject the comment. Yes, I get plenty of spam. But I'd rather not put the few people who leave legitimate comments through additional hassles trying to pass the captcha tests when I'm going to preview the comment anyway.