I've noticed that I get more feedback on blog posts on Twitter than I do via my blog's commenting system. People will see my tweet about a new blog post and reply via Twitter, rather than add a comment to the post itself, even though the commenting software I use allows logging in with your Twitter account. Maybe this is where blog commenting now lives, in the Twitterverse. Also, Twitter users quite often tweet links to interesting blog articles they have come across along with their comment and any ensuing conversation takes places on Twitter, not on the blog itself.

New services like Pushnote, that allow users to comment anywhere on the web via a browser extension, are also encroaching on the space usually filled by blog commenting software. There are still times, however, when only a traditional commenting system will do, such as replies which correct mistakes in a technical article. These need to be stored and displayed with the article on the original website. Maybe the software that will pull all these disparate conversations together has yet to be written.