We are close to releasing threaded comments to all of MindSay. In a few days, all of MindSay will be using the new comment style. While we won't be able to show the comments in a semi-transparent layer like we do now, the overwhelming feeling seems to be that people welcome the change. Give it a chance :)
UPDATE: Because we love you -- MindSay user -- we have decided to implement HTML in replies. This means you can put pictures, quizzes, etc. in your reply.