You should also be aware that there is no guarntee, even if you do everything correctly, that you will recieve notification that someone recieved or read your email or attachment. Many email systems disable this feature at the site level and many email clients allow you to turn it off individually. These are designed to make less information avialable to spammers.

Hope this is useful

Corrected some typos. I mean my spelling is bad but not THAT bad 8^)