One of the reasons I switched from Blogger to WordPress was the ability to provide a feed for comments, not just posts.
I’m subscribed to the Unofficial Intel Blog, run on Blogger and Blogspot. There is some great conversation going on in the comments of his/her posts, but I only stumble across it when I remember to go to the site and manually click on each post and read the comments. RSS feeds and syndication automate this process, which is the main reason I read 99% of stuff on the web via feeds. I usually can’t be bothered to remember to go back to a site, then look and decide what I’ve already read, and what’s new.
At any rate, if you’re interested in the conversation about Intel that’s going on in the blogosphere, don’t miss the comments over at the UIB.
EDIT. coComment can help with this somewhat, by providing you a feed of all comments that appear in posts you’ve commented on. They support most blog engines, including Blogger. But I’d still like to see the option of a feed for comments.
EDIT 2: FrankieB points out in a comment that once someone starts tracking comments on a blog using coComment, a feed of all the comments from that blog becomes available. At least, that’s how I think it works, since only 2 of 20 or so UIB comments are showing up. At any rate, the coComment page for the Unofficial Intel Blog has a feed link. I’m subscribed.