Wietse Venema posted a note to the postfix-users mailing list about the 25th anniversary of the Postfix mail server. As can be seen, it had a pivotal role in bringing more awareness of open-source software to IBM. Beyond that, of course, it is an excellent piece of software in its own right.
As a few on this list may recall, it is 25 years ago today that the
"IBM secure mailer" had its public beta release. This was accompanied
by a nice article in the New York Times business section.