Offer the clients a complimentary evaluation, or have them opt into another list just for early about this new and exciting product. This will help ensure you're only testing the subject line. http://thenoodlebox.com/__media__/js/netsoltrademark.php?d=totalintranet.com%2F__media__%2Fjs%2Fnetsoltrademark.php%3Fd%3DLaunchhappy.co