troll-farm propagation servers

usenet news servers have always invited spam and troll-farm infestation,
and the bigger they are the more abundant their propagation seems to be;
this short list includes some of the most notorious servers of all time,
(of course every smaller news server would appear further down the list)

googlegroups.com (extinct)
newsdemon.com
theworld.com
giganews.com
news.uzoreto.com
eternal-september.org
blocknews.net
astraweb.com
usenetserver.com
easynews.com
etcetera...