This is from the official Haloscan blog:
Haloscan is currently experiencing some server difficulties. I want to assure you that we are aware of the problem and are hard working to fix it.
Users may experience problems loading, submitting or moderating comments with Haloscan during this period.
Please rest assured your comments are still safe and secure on our system.
We apologize for any inconvenience.
More information to come.
Update 1: Users can now view comments, but can not add or edit comments. This will take up to 24 hours to restore.
Active blogger comment thread.