Ok, so since the release of Sitefinity 4, we've been saddled with a pretty basic commenting system...for example still we have no hierarchical threads, email notification system, and no ability to add a thread to a generic page. At the very least I'd like to get an email when I get a comment so I don't have to check back daily for feedback right?
So, say goodbye to Sitefinity Comments, and hello to DISQUS on sitefinitysteve!
Note 2020-09-24
These are now in a Github repo you can fork and use Check it out here
Later versions of Sitefinity now DO contain a native comment widget, although it's really bare bones, if not bad. Disqus still might be a good idea, I just don't have MVC widgets.