Diminishing Comments

I’ve seen a number of blog designs that display the comments made by readers at a much smaller font size than those of the author. I’m trying to determine if this is an attempt at lowering the value of the comments. I’d guess in most cases it is used as a visual differentiator to separate the post from the comments. I’m sure at least some people want to see what they’ve written stand out in size against other’s reactions to it. Is this good for conversation?