I was actually thinking of something like this. I was going to make it my first RoR project but that might just be to ambitious. Anyways, plain and simple,

coComment is the only service that allows you to enjoy the full potential of blog comments on the web. Before coComment, the blogosphere was not a global conversation, but tons of fragmented, hard to follow, and untrackable discussions.

Using coComment, you can now keep track of what you have been commenting on, display your comments on your blog, and see what is new in the discussions you are participating in (if other users are also on coComment).

One con (at the moment), is that “users can only track comments from blog posts that they have actually commented on, and only comments left by other cocomment users are shown.” ((Michael Arrington, coComment visit to Silicon Valley)) But this was a day or so ago. I have to check the new version out myself as I’ve just signed up a few moments ago.

Along with their news yesterday about version 0.4c being released, the team also mentioned the fact that there is now a Firefox extension for coComments. This addition, for sure, will make things a bit easier than having to use a bookmarlet on the user’s computer.

There might be one small gripe though. As I was taking a look at coComment’s Blog Integration section which lists which browsers and blog/CMS/site-platforms it supported, I read that Movable Type blogs must have the following format,

<title>blog name : article title</title> or
<title>blog name | article title</title>

Otherwise, the comment (in coComment) will show up as “(untitled)”.

So, seeing that, there might be an issue of having everyone involved have a standard way of templating their TITLE-tags. I, for one, see this as a big thing (so it ain’t “small” after all). If this is true, and hasn’t been addressed in it’s next iteration, coComment is pretty much forcing everyone to do “this and that.” Then again, we’ll see how this plays out with Microformats. So if you are listening/reading this oh-Lords-of-coComment, please do let us know. (Then again, I just signed up and haven’t gotten to play around with coComment that completely yet.)

All in all, the service is practical and very useful for those that like to read and interact with different blogs. It’s great for coComment to have gotten around and implemented something useful to the millions that are very involved with interblog-interactivity. In it’s current state of version 0.4c, I just can’t wait to see the other features it will have when it rolls out from “beta”. Pretty much, like all the other “Web 2.0” application-sites. =)

Update
My follow-up on coComment