One of the downsides I've seen with Blogger is its lack of integrated comment threading. People can comment but comment threading is unavailable.
I think debate is encouraged when you can respond directly to someone.
So I have installed IntenseDebate, which is a widget that permits comment threading. It was easy to integrate the code into my template and now all new posts will have comment threading.
I hope you will find it easy to use and useful. Please let me know if you have problems commenting on new posts.