I'm trying out a new comment handler on my blog. It's IntenseDebate. It allows you to subscribe to be notified via email of additional comments on a post (as you always could). The feature I'm excited about is that it allows you to post a reply to a specific comment. It also allows you to subscribe to just the replies to your own comment if you wish. So you wouldn't get an email to every comment on that post, but you WOULD get an email notifying you whenever someone specifically replies to your comments. You can also comment & reply to comments via email.
It allows you to post comments using services like Facebook, Twitter, and OpenID. Or you can sign up for an IntenseDebate profile but you can still simply comment without one as a Guest.
It is also integrated with Google Reader & Bloglines allowing you to read and post comments directly from your RSS reader.
If you want to see the details here is the IntenseDebate features site.
This is brand new to me & I'm still figuring out how it all works, but I think this will be a good thing. Let me know how you like it!
Update: December 8, 2010 1:32 PM
To comment from Google Reader install this Firefox Add-On gReader Comments found here:
https://addons.mozilla.org/en-US/firefox/addon/6128/
Shoot, it has not yet been updated to work with the latest version of Firefox. :(