Sometime back, Steve Rubel wrote this. And then, co.mments appeared. It is true that comparisons to coComment are inevitable. They both track conversations, they both support RSS, they both begin to function as soon as a bookmarklet is added, they both have minor glitches when it comes to integrating with a blog and they both promise a lot.
Until coComment entered the Commentosphere, the state of a blog hopper reading and commenting in several blogs was mostly clueless. Like many bloggers pointed out, there were several conversation killers that ruined several potential "interesting conversations" to merely an unattended comment which the blog owner missed. With additions like these, the good old commenting system gets a face-lift.
So now it is possible to display the comments you made elsewhere in your blog, track the conversation and get alerts in your feed reader. If these two services were to become popular, which they most likely will, it will mean R.I.P. for primitive commenting systems and Comments that open in pop-up windows. Bloggers who still use those, it's time to part ways and move on.