How can I avoid my newsletter from being considered spam?

Question

I want to send out newsletters and email notifications. I am having a hard time understanding the techniques of getting into the inboxes of yahoo, especially hotmail. I notice that myspace and other popular service websites are getting through every time. What is the secret? I am using php's mail function in a php/mysql environment.

Answer 1

Sending it to people UNSOLICITED is spam

Answer 2

Write in big letters
"THIS NOT SPAM, OK?
NO, REALLY ISN'T.
HONEST"

That should do it