Comments on blogs are a foundational element for building a community.

With twitter-spawn friendfeed, adding comments to tweets, the question is, could friendfeed and something like Disqus merge to offer cross community comment streams?

Right now, some think comments on Disqus or friendfeed are heading for a black hole.

But, imagine if a blog post linked to in a tweet displayed the comment thread from disqus in the friendfeed stream, and if comments on friendfeed would show up in the Disqus thread on the blog post.

That would spawn some very very interesting communities and discussions.