If a comment is held for moderation an email message is sent to the comment author with a link to verify the comment author's email address.
Absolutely not. This plugin uses the
commentmeta table new to WordPress 2.9
This plugin doesn't notify you. It sends mail to the comment author.
You should try configuring the plugin to use SMTP!
If you have already done so, please check your settings!
If it's only Yahoo/Gmail/Hotmail/xyz users who don't receive your messages, but it works well for others, then it might be that your host has a bad reputation and is blacklisted. (I've seen that happen so many times. Notice the "might".)