Django still powers a lot of the DISQUS infrastructure. That said, we're in the process of breaking certain parts of it off into independent services and out of Django. But Django will be the main component for the foreseeable future.
Don't misread what Fluxx is saying. The core of disqus and our primary data flows are still powered by Django and that won't change. New servers which are less complex (e.g. the realtime system) are generally written on top of Flask.