Better separate comments in content and discussion sections

Currently, it is very difficult to distinguish individual comments in content and discussion sections, these should be better visually separated, i.e. use more padding, display meta information (i.e. time, user name) before the actual content and use it as a visual separator, display Gravatar for users (using profile emails or emails entered by anonymous users). Look at existing blogging systems for inspiration, post comments in particular (see Posterous).