Still, this primitive list server was a great help to people. Before this first list server, a member of a mailing list discussion had to know the email addresses of all other members in order to send a carbon copy message to each person on the list. With this first list server, one static email address automatically distributed to the entire dynamic list, a process that simplified communication among group members.

As the email list service became popular and more lists were created, the need for automation increased. It became clear that a computer program that could add and remove people would be a great time-saver. Eric Thomas, at the Ecole Central de Paris in France, wrote such a program in 1986. Thomas named his program Revised Listserv, since it was a revision of the original listserv idea. Revised Listserv was eventually shortened to the all-capital LISTSERV.

Initially, Revised Listserv was free to members of BITNET and ran on IBM mainframes that used the VM operating system. Thomas later ported Revised Listserv to the VMS operating system that ran on Digital Vax mini-computers.

A list server for UNIX
Although Revised Listserv (the first automated list server) was available for machines that ran the VM or VMS operating systems, it wasn't available for machines that ran the UNIX operating system.

At the time, UNIX systems were becoming very popular and widely available. A great appeal of the UNIX operating system was its ability to run on less expensive machines compared to costly machines that ran the VM or VMS operating systems. In response to the growing demand for a UNIX list server, Anastosias Kotsikonas, more commonly known as Tasos, wrote a UNIX list server program called "Listserv for UNIX." Tasos later changed the name to ListProc to avoid confusion with Thomas' LISTSERV.

At the time, ListProc was free as C source code and ran on a variety of UNIX platforms. Eventually, Tasos sold a later version of ListProc (version 6.0) to CREN. After parting ways with CREN, Tasos began work on another list server.

Tasos was later replaced at CREN by Rob von Behren, who helped ListProc rise to a new level by developing features that allowed fast mail scanning and confirmation of subscribe and unsubscribe messages. By this point, the government-funded Internet was emerging.

To keep ListProc's features technically current, Rob von Behren worked on the development of a Web interface, incorporated a database for storing subscriber attributes, and increased the program's customizability. While ListProc's advanced features appealed to many UNIX users, some users preferred a simpler program. Consequently, a large number of home-brewed list servers appeared on the scene during the early 1990s.

One example of a home-brewed program was Majordomo, written by Brent Chapman. Chapman volunteered to act as postmaster when the System Administrator's Guild decided to create over a dozen mailing lists. With limited time, Chapman was most interested in finding a list server program that could automate subscribe and unsubscribe requests, simultaneously manage numerous mailing lists, and automatically process other end-user requests.