Do you use e-mail? If you forward something to someone, and they forward it to someone...pretty soon strangers have your e-mail address. When I forward an e-mail, I always make sure I delete any names and e-mail addresses on the page. When I send a joke on to many people, I use BCC (which stands for Blind Copy Sent, I don't know where the other C came from) and their e-mail addresses do not show up to each other.