>This is not new. Many of the mailing lists that dominated the discourse of the early Internet in the 1990s operated under a similar rule. The novelty is that it disappeared almost entirely for decades.
Anecdotally, I believe this rule was followed implicitly and often subconsciously and probably through some of the peak blogosphere era, despite blogs being accessible by the general public at the time. People were still looking for their tribe to escape the intellectual, creative, or censored dullness of their local surroundings.
The concept of ratting out people who were looking for the same thing would not occur to most people. They prized the discussion they couldn't have elsewhere more than the specific points being made. It'd be like the pilgrims going back to England and complaining to the English about all the other crazy heretics in the new world.
The whole thing started disapearing when going "viral" on social media started becoming a thing.
FYI gag as in "gag order" not gag as in a joke.
In case anyone else was confused about this as I was :)