Mail (also known as Mail. app or Apple Mail) is an email program included with Apple Inc. ‘s Mac OS X operating system. Originally developed by NeXT as NeXTMail, a part of their NeXTSTEP operating system, it was adapted to become OS X’s Mail application following Apple’s acquisition of NeXT. The current version of Mail utilizes the SMTP, POP3, and IMAP protocols, and supports Yahoo! Mail, AOL Mail, Gmail, MobileMe and Exchange via IMAP.