First, the plugin works, very useful thanks for it.
I have only one problem : I use Social plugin.With this plugin you can make comments on posts using your twitter or FB account. When someone try to add a comment with his twitter or FB account, AVH says automatically : cheting,huh? Or something similar and the comment not approved.
Would be useful if the plugin would have an extra option where we can add domains to the whitelist. Like whitelist of ip address.