I wonder if anyone else has the impression that a good ding-dong on a thread seems very often to attract swarms of spammers and inspires trouble-makers to start up new threads on controversial and divisive subjects and keep stoking them?
Most of the time the forum goes along as usual, lots of conversations and exchanges, mostly goodnatured chat or reasoned debate with the occasional raised voice. Sometimes a more heated debate gets going, where more people join in. After that, there is a rash of angry threads which seem to come from nowhere, started by people I have never heard of before, and lots of posts wanting us to go to someone's website and presumably spend money there.
I assume they see the arguments on a search engine, and think "Is this a private fight or can anyone join in?" so they join set GN and set up their boxing ring (or their market stall on the edge of the bare-knuckle bout)
I don't include here the anger in some threads from established posters - they are not the opportunist hitchhikers I am talking about.