I've installed the Disqus comment system, and new comments seem to be fine, but none of my existing comments are converting over to Disqus comments. Here's an example:
I was able to post a new comment using Disqus, but I had 2 existing comments on that post that are not showing up. They still show up in my WP Dashboard, so they exist, and under the post it says "2 Comments" but they don't appear in Disqus.
I tried the migration wizard, thinking it may have had something to do with changing my domain name a few weeks ago (before installing Disqus) but that made no difference.