Suzanne S. Barnhill shared this with us in
microsoft.public.word.newusers:

especially to actual Usenet NGs (ones not on the msnews
server), where a more rough-and-ready posting style apparently
obtains.

You mean a "hit-and-run" posting style.
At home I have my default "don't feed this troll" message, with some
nice ASCII art. ;-)

Anyway your observation may be right in the case of the Microsoft
newsgroups.
Forum users over here may be ignorant and clueless (some, not all) but
don't stick around, because of the specific nature and sheer volume of
messages.

On the other hand, I have seen other forums (like the user forum of my
ISP) where the opposite is true: the newbies do stick around, and the
worst part of the year is when high school and college students have
their exams (=now). One might wonder if they shouldn't study...

--
Amedee Van Gasse