[BirdOPrey5]

Deleting the if statement around

                <vb:if condition="$show['subscribetothread']">
                    <option value="1" {vb:raw emailselected.1}>{vb:rawphrase instant_notification_by_email}</option> 
                </vb:if>

will just show the option... but the code to handle this choice must still be programmed via php probably in one or more plugins and you'll need a new phrase for an email to send out- this is a pretty significant amount of coding to do this. Also the very fact it's not an option by default worries me there could be performance issues.