IntenseDebate developers have been quiet for a very long time now. There have been no updates from the developers. The plugin seems to have received no major feature update.
However, there has been an update today. A new feature has been added. It is nothing big. Though it does confirm that the service is still alive and is not being discontinued by Automattic.
The new feature adds a Re-check For Spam to your moderation page. It comes handy to let the service go through all approved comments from the past and look for any spammy looking comment that might have bypassed the filters.
This might come handy for people who do not get many comments on their blogs. But if you are running a popular blog getting tons of comments, you would want to avoid clicking this button as it might mark a lot of genuine comments as spam which you would have to verify manually.