If I log in under Disqus I’m banned from commenting on Real Clear Politics. I have to log in under the RCP site. I’ve contacted them again and again but no help or even a response. I gave up.
I think a few sites have a separate gateway in that manner...Townhall eg. They shifted from a native comment system to Disqus and Townhall comments are visible on Disqus but one must still log in to Townhall.