The installer tells me that Mail.appetizer could not be copied to ~/Library/Mail/Bundles. What can I do?

This might be an access rights issue. You'll have to install Mail.appetizer manually:

• Quit Mail
• Copy Mail.appetizer.mailbundle to ~/Library/Mail/Bundles
• Open Terminal and type:
  defaults write com.apple.mail EnableBundles YES
defaults write com.apple.mail BundleCompatibilityVersion 1
• Restart Mail

Where do I find Mail.appetizer's preferences?

Mail.appetizer does not have its own menu. You'll find the preferences panel in Mail's preferences.

Can the next notification be shown automatically after some time?

Yes, you have to enable "Automatically show next message after … seconds" in the preferences.

Can I limit notifications to chosen mailboxes like my Inbox?

It was the #1 request to make Mail.appetizer 0.9 notify not only about Inbox messages. Now, that Mail.appetizer 1.0 finally displays notification for all messages, it's the #1 request to limit it.

I'm going to add this functionality in a later release (see further development). For the meantime, you can Control-click the close button to discard all notifications for the current message's mailbox.

How can I move and resize the notification window?

Open Mail.appetizer's preferences panel to move and resize the window.

How do I open an appetized message in Mail?

Click on the subject to open the message in Mail.

How do I mark an appetized message read?

Control-click the notification to instantly mark the message read.

How do I delete an appetized message?

Shift-Control-click the notification to instantly delete the message.

Depending on your settings the message is deleted or moved to the account's trash folder. Use this option with care, as you might not be able to undo it.

Is Mail.appetizer compatible with other Mail plug-ins?

Mail.appetizer does not show notifications for Hotmail/MSN messages fetched by the httpMail plug-in.

Other plug-ins should work fine.