It's called a Disqus shortname, not username

barryclark · barryclark · commit 78d61e44ce03 · 2014-06-16T00:40:42.000-04:00
diff --git a/_config.yml b/_config.yml
@@ -28,7 +28,6 @@ footer-links:
   rss: # just type anything here for a working RSS icon, make sure you set the "url" above!
   twitter: jekyllrb
 
-# Your disqus username, entering this will enable commenting on posts
 disqus: 
 
 # Enter your Google Analytics web tracking code (e.g. UA-2110908-2) to activate tracking
