I think that the definition of trolling really depends on how old you are/ how long youve been online.
In modern terms/ to younger users, trolling is a vague catch-all term for
any antisocial behaviour that has lost its specific meaning (much like the way that ironic nowadays means anything that sounds like bad luck, rather than the previous definition). Trolling (in its modern definition) apparently now includes blatant bullying/ unsubtle baiting - I've heard people use it as a shorthand for offline bullying too.
For me, trolling meant trying to change the subject online to get a reaction, usually in a disingenuous/ sly way (not to be confused with flaming, which is saying something brazenly to get an equally hysterical reaction). Trolling is dog whistle behaviour, the art of bringing something up without actually going as far as saying something libellous.
Look at politics, and the way that some people will happily confuse two issues (or try to make a link between them) trolling (to me) is the kind of Im just mentioning a few things in the hope that you will jump to a certain conclusion behaviour.
Trolls will happily slip things like immigration or crime or religion into an argument, stand back and watch the reaction of others. The classic example is the #justsaying / #justmentioning hashtags on Twitter where you put a couple of seemingly unrelated things together and waiting for someone else to join the dots.
Funnily enough, some of the contributors to this thread have engaged in their fair share of trolling in the past such as trying to derail threads by mentioning certain (unrelated) hot potato issues that they know will get people to react.
There are plenty of well established touchstones on this Forum that you know you could lob into a thread and will lead someone to bite it doesnt even have to be party politics/ immigration/ football. Just casually mention Beeching/ the Barnett Formula/ ticket barriers/ staff working at Christmas/ guided busways/ cyclists on trains/ prams on trains/ concessions for pensioners/ excessive TOC profits/ drivers only having to push a button/ guards always hiding in the back cab/ all enthusiasts being frustrated wannabe drivers (etc) into an existing thread, step back a safe distance and see the sparks fly.
Take the recent thread on GOBLIN wiring. I could derail that by saying something like GOBLIN is only getting electrified because its in London and London gets everything it wants whilst oop North we only have Pacers or maybe Im sure that this will be done on budget and on time like Crossrail because Londoners know how to organise a project properly, unlike those overbudget delayed schemes oop North no wonder they cant get more investment when they are so bad at managing the projects that they do have both would be gross exaggerations of course, but I guarantee that mentioning either of them on the GOBLIN thread would see more people reacting passionately (than those who are trying to have a sober conversation about the infrastructure of this particular line).
Now, I wouldnt do that, but I could give examples of where other people have trolled threads by trying to make them about some touchstone issue (instead of what the OP intended them to be about). Im sure Im guilty of it a few times too (let he who is without sin and all that...)
However, thats nothing to do with what this lady did she wasnt being subtle, she was expressing her feelings very blatantly. Id have called that flaming, from my earlier days online deliberately stoking controversy, saying blunt things to try to get a reaction (unlike the subtlety of trolling).
"Flaming" and "banter" seem two sides of the same coin - the act of saying something brazenly outrageous for the sake of getting a reaction from people (the Frankie Boyle approach). No subtlety required.
The only reason Im not sure that flaming is the most appropriate word here is that she wasnt addressing the abuse directly
at the couple concerned (presumably because they arent on Social Media if they were then she may well have sent it to them, but thats now a moot point), she doesn't even seem to have been saying this directly to anyone who;d be outraged. Maybe there needs to be a different word for saying strong things
about someone versus saying strong things
to someone? Neither of these is trolling in the old sense.
(on a different tack can you imagine the tabloid hysteria if it had been a BBC employee who had doorstepped this woman? The Director General would have been dragged before some Parliamentary committee, the tabloid reaction would have been much worse than the Brand/ Ross/ Sachs story... sorry, thats
me dragging the conversation off in a different direction to try to get a reaction which is trolling... yes, I know, I know...

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