Sorry but I don't get it, how is the riddle different than a normal password? Some sites request certain characters of your password, which I find just slightl

Sorry but I don't get it, how is the riddle different than a normal password? Some sites request certain characters of your password, which I find just slightly better than asking for the full password, but extremely more annoying for the user. Can't see the advantage of the riddle, seems to be the same approach. Also, if I have to remember a different nursery rhyme from every website out there... well, I'm sure you see the issue here. Not to mention these rhymes -or the correct answers to the related questions- would have be stored in plain text (or actually reversible encryption) at server side, instead of a hash of the user's password.