Nice lightweight plugin + Disqus with refcontrol Rated 4 out of 5 stars
Nice plugin, but people who have problems with disqus comment boxes need to have comment box location host as referer setting for disqus.com in "long form" as http://www.example.com not as www.example.com.
Little bad for users who use multiple pages with disqus comments, and want to use this lightweight plugin, but atleast now you know where problem lies.
P.S. When contacted disqus developers were determined to keep their "security" feature that can be easily spoofed :P