Qué lástima, porque yo sí tengo una cita[1] que describe el uso stealth banning (o hell banning) durante inicios de los 80, y por lo tanto refuta el enunciado de >>7:

>I pulled down a handful of early Citadels' source code to look. The earliest Citadel (v 2.10, circa 1981) doesn't seem to have the feature. Citadel-86, from a few years later, has a "twit bit", but it's more as mmoncur describes. GremCit (c.1987), one of the earliest I remember using — as the archive page notes, "This code served as the root for almost all subsequent Citadel development in the Seattle area" — has a "problem user" bit, which does sound like what waxpancake is talking about: posts by such users are only visible to "aides" (aides are non-sysops who've been given some extra admin-type privs), but can also have their general visibility toggled on and off on a per-post basis by aides. It looks like that feature migt have come from Stonehenge (c. '85-'86), but its archive uses some compression methods that modern unzip implementations don't seem to support.
[1]: http://ask.metafilter.com/117775/What-was-the-first-website-to-hide-trolls-activity-to-everyone-but-the-troll-himself#1687289