I am getting four or five thank me later emails a day for comments on my site. No text of the comments is included and there are no comments on the blog. I am guessing this is spam that is caught by akismet or si-captcha, but your plugin thinks that valid comments were made.
I don't know why the thank yous wind up in my inbox.
Does the plugin check the validity of the email?
Keith
WP v2.9.1