The first thing I really like about Disqus is that it brings community from other services back into my website. Disqus looks at Twitter, Friendfeed, and other services and pulls in "reactions," which are posts that contain links to a given journal entry. It will even resolve shortened URLs. Last week, I posted about a fun transaction between me and some of Tony's friends in Thailand. Tony commented on the journal entry in his Twitter feed, which was picked up by Disqus as a reaction:
This sort of feature is exactly the reason I moved over to Disqus from Wordpress' standard commenting engine. There is one issue, however. Because I use Alex King's Twitter Tools, each journal entry is also posted as a tweet to my personal Twitter account. Disqus picks all of these entries up as reactions, which is something I'd rather it not do. This would be a difficult thing to try to filter out, so I'm not expecting it to be added as a feature anytime soon.
Another feature that shouldn't be overlooked is that people can simply reply to a comment notification email to reply to a comment.
So far, so good!