Though we do a check on validity of domains while user provides email addresses, it would be also good to indicate the email address in the "email was sent...." notification messages.
Scenario:
User entered email id as "apeter@redhat.co".
Actual Result:
As ".co" is a valid domain Zanata will not generate any error message, but provide a notification that email was sent successfully. Thus user will not be aware of the error in the email id and wait for a notification from Zanata.

Thus, indicating the email address user has provided in the notification message will act as a second check point for the user to ensure the correctness of information provided.