RSS 2.0 already does comments in feeds. I think that syndication (RSS , Atom, etc.) will be bigger than blogs but without blogs RSS wouldn't be where it is today.

From A VC: It's The Feed Stupid:

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So, this means that the smart money is going to go into the feed space. Because that’s where the action is. Forget AdSense. I need contextual ads built right into my feed. Forget Typepad links, I need the links built right into my feed. Same with comments. And the feed needs to be two way. Atom has that capability I am told. So let me comment right in the feed. That’s a hell of lot better than Trackback.

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