Had your plugin installed in its latest carnation and encountered a problem with Disqus, the comment system for WordPress.
When installed, your plugin seems to disable commenting through Disqus. On my site I got this: Comments Closed message.
When I disabled Spamfree WordPress, everything worked normal again.
Just wanted to let you know that this happens. Right now I've chosen to temporarily disable the plugin, as I really need a decent comments system for my site.
Edwin van der Veer