I have been handling a lot of WordPress development at work recently. At my job, all of the blogs are using IntenseDebate to handle blog comments. This presented a problem to me recently with launch of a new theme I was working on.
The problem is that on a post, IntenseDebate would show one number of comments while the post detail info would show a different number. I tried several different methods of fixing this to no avail. IntenseDebate does not have much in the way of documentation, and the system itself leaves a lot to be desired.
To get your comment numbers to sync, you need to use the WordPress provided template tags,
comments_popup_link(). This fixed the problem for me.
I hope that this helps someone else, as there is not much info on this out there that I could find. And avoid IntenseDebate if you can.