Not so long ago, the likes of John Nimmo would be living in well-deserved obscurity.
Nimmo is a misogynist racist who has a penchant for sending threatening messages to women. Before the internet and the advent of social media, he would doubtless have festered alone in his South Shields bedroom and his hate would have been shared only with whichever other losers he happened to speak to.
But in our digital age, Nimmo can make contact with pretty much anyone at the touch of a button.
Two years ago he did exactly that to Stella Creasy, the Labour MP, and Caroline Criado-Perez, the feminist campaigner, sending them abusive tweets and getting an eight-week prison sentence for doing so.
Now he is at it again, this time sending anti-Semitic death threats to Luciana Berger, the Liverpool Labour MP. She would, he told her, "get it like Jo Cox". He warned her: "Watch your back Jewish scum, regards your friend the Nazi", along with a picture of a large knife.
Ms Berger told the court where Nimmo is being tried that his words caused her "great fear and anguish". She said the tweets left her in a state of "huge distress" and "caused me to feel physically sick being threatened in such a way".
I imagine that you are shocked to read about such behaviour. No decent person could fail to be. But Ms Berger won't have been. I certainly wasn't. Nor will any prominent Jew. Not because the behaviour is in any way acceptable. Rather, because it is so run-of-the-mill.
Ms Berger receives anti-Semitic abuse every day. In spades. Indeed, you will not find a single prominent Jew with a Twitter or Facebook account who does not regularly receive anti-Semitic abuse.
When I wake up and check my Twitter feed it rarely contains fewer than 10 anti-Semitic messages. More often than not it's far more. Another 20 or so come during an average day. And that's after I have blocked more than 300 different tweeters - a number that increases every day.
Some even amuse me, such as the recent claim that I "lead British Zionists with their propaganda to enable them to control UK". Another tweet informed the world: "Pollard is the chief protagonist of Zionist supremacism in UK. He controls MSM."
MSM is an acronym for mainstream media - which means I apparently control all British media. Which would be really useful, if it were true. Sadly, I can't even control my own kids.
Some comments are threatening. One notorious anti-Semite that I had previously blocked started informing her followers that I was in the habit of ringing her voicemail and had left abusive messages threatening to rape her. She also posted a tweet suggesting that someone "pop" me off.
In my experience, the police have been entirely useless. Last year I had to explain what Twitter was to two PCs from the Met who had been sent to talk to me about a threat I had reported. Though they had heard of it, they had no real idea what it was.
This is an epidemic of hate. And with the odd exception, such as the clear death threat to Ms Berger, nothing is done about it. Certainly not by Twitter. I have given up reporting the culprits, since not once has Twitter taken any action against them. Free speech, innit?
But one thing puzzles me. Have the likes of Nimmo always been with us, and has social media simply given them a tool and a voice they didn't have before? Or has social media itself raised the temperature and caused much of the epidemic?
For most of my 51 years, anti-Semitism was something I encountered only fitfully; the odd unthinking throwaway remark or "joke". Certainly nothing that would give me pause for thought.
But the past few years have been different. I have not gone a day without encountering it. As a journalist, I have reported the spate of such comments from Labour members with astonishment that anti-Semitism can have entered the language of a mainstream party, however marginally.
My hunch is that it has always been there, but we simply did not hear it.
In the years after the Second World War, no one voiced anti-Semitism, even if it lay buried deep within their psyche. Even Jewish jokes were rarely told in polite company. But as memories faded and the Holocaust grew further away, social wariness of Jew-hate dissipated.
History then reasserted itself. It's not called the longest hatred for nothing. And the kind of anti-Semitism that once remained private, behind closed doors, now has the megaphone of social media. And that, we surely know, is not going anywhere.
Stephen Pollard is editor of 'The Jewish Chronicle'