Does the program know the emails that already got a response

[devicode]

I just want to confirm that Response Mailer will not respond to the same incoming message more than once. Because I also need to receive the messages with Outlook Express, I cannot have Response Mailer delete the messages from the server.

Response mailer knows the difference between emails that have already gotten a response and ones that haven't?

[devicode]

ResponseMailer keeps track of each message it receives and ensures that it responds only once to any message that meets the filter condition.

In addition, will not delete any messages from your mailbox unless you specifically add a 'delete message' action. This way you will be able to download the same messages in your email client such as Outlook express, Outlook, Eudora, Thunderbird, etc.
You can set up your email client to delete the emails after a week or so.