Comments on blogs posts and articles have in the past generally been a good measurement of how people have engaged with content, but as the web becomes more social and realtime, the conversation is going all over the place, and there are other ways that pe

You see it on Twitter and on Facebook. You see it On Digg, on FriendFeed, etc. People are still commenting on blogs, but theyre not always choosing the blog comments section as their venue for furthering the discussion. This is why you see other buttons on content sites like the Digg button displaying the number of Diggs a story has, or the Tweetmeme button displaying the number of retweets.