Post price & blog reliability

This new service has been reviewed enough.
People considering it like a big threat for blogging community, and people... well just considering it the last buzz.
I'm not here to judge anything. I simply think that, in the end, market will award good ideas and forget bad ones.

Instead, I would like to highlight comments prices (can they be used for a rough ROI calculation?)
Buy Blog Comments pays about 0.20$ per post.
Pay per Post pays "from $5 to several thousands of dollars" (the more traffic you have, the more you earn)
Review Me pays "$20.00 to $200.00 for each completed review that you post on your site"
(if anybody konws more of these services, please let me know!)

But there is something else.
What if paid comments will become a norm in the future?
Will it happen something different from magazines?
Or TV?