“This article describes the different ways to send e-mail in PHP and comments which one would be fastest depending on your circumstances.”
— Manuel Lemos
1. PHP mail() function
2. SMTP server relay
3. Sending urgent messages by doing direct delivery to the destination SMTP server
4. Sendmail program
5. Qmail, Postfix, Exim, etc..
6. Microsoft Exchange pickup folder
7. Putting all recipients in Bcc headers
8. External Web services
9. Caching message bodies
