Well done for working out how to use the headers functionality of the mail() function. I assume the message count stores IPs as it doesn't store cookies.
But this sort of thing probably shouldn't be on x10, some admins may object to it, so you may want to remove it...
Hopfully you realise that things like that can be used by unscrupulous individuals for spamming/phishing purposes, and that you will be held responsible when it is discovered (and it will be!)