Companies had been using crude forms of Instant messaging within their own networks for over forty years, but the idea of presence, i.e. who is logged on at any given time, was non existent.
It was not until Appelman, and his colleagues at the Thomas Watson Research Center, first began to write programs on the mainframe system letting each other know when they were actually online, that modern day Instant Messaging was born.
Appelman was able to turn complicated IBM politics to the advantage of TCP/IP, open systems and Internet standards.
This was not an easy endeavor given that at the time IBM was pushing hard a competing family of internal protocols called Systems Network Architecture.
In the end, the work of Barry Appelman proved critical to the IBM's adoption of TCP/IP and its early embrace of the Internet.
Particularly noteworthy was the innovation by Appelman and one of his development managers Matt Korn to get voice and video flowing over IP back in 1987.