The original version of Listserv, quite a few incarnations prior to its current state, was introduced in 1981 on the BITNET network. It lays claim to being the first list server available (besides human labor). While Listserv and ListProc were the two main, freely available list server packages for the subsequent decade, the scene went commercial in the mid-1990s.
Of the four products we will discuss, only Majordomo and ListProc v6.0 are entirely free for use -- newer versions of ListProc are commercial. Because ListProc v6.0 is quite old at this point, Majordomo remains the only major, actively developed free list server available. Some will even estimate that it is the most widely used list server of all.
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