Broken careers, ruined reputations, jail-terms, bullying, and virtual war. Exactly when did Twitter become an exercise in causing as much mayhem as possible in 140 characters or less?
The wildly popular micro-blogging service, more than 500 million users and rising, has recently crossed the line from reporting on the news to causing it.
And while it is greatly enjoyed by millions, the free-for-all, virtually unregulated world of instant global communication now appears to be spinning out of control, causing serious problems for the traditional media, celebrities, politicians, sports stars and ordinary users.
From spreading outrageous libels linking politicians to high-profile child-abuse cases to identifying victims in sexual assault cases in a number of instances, still before the courts, Twitter has increasingly become a tool – in the wrong hands at least – for causing havoc.
A big part of the problem is that social media allows people to broadcast offensive, illegal or in many cases, incredibly stupid behaviour to the world.
Just this month alone, a man was arrested in Kent in England for tweeting a picture of himself burning a Remembrance Day poppy while another English police force is investigating death threats tweeted against Republic of Ireland footballer James McClean because of his refusal to wear the poppy on his jersey when playing for Sunderland.
Elsewhere on social media, the wife of the Speaker of the House of Commons in the UK, Sally Bercow, had her high-profile Twitter account suspended after reportedly naming a young woman at the centre of a child abduction case.
This followed another case where police arrested and charged two people who had used twitter to name a woman who was raped by former Welsh international footballer Ched Evans.
In the case of Ms Bercow, she had also been amongst the thousands of Twitter users who wrongly named, or linked, former senior Tory Lord McAlpine with child abuse claims, an incident which could lead to the biggest libel case in UK history, with lawyers for the politician threatening to go after up to 10,000 Twitter users after their current affairs programme Newsnight erroneously claimed a top Tory politician was implicated in a paedophile ring.
After being warned that she could be amongst those targeted by lawyers representing Lord McAlpine, Bercow tweeted to her 57,000 followers last Sunday night: "Thanks for phone calls/texts/tweets. I guess I'd better get some legal advice then. Still maintain was not a libellous tweet – just foolish."
However, the wife of the Speaker, who might be expected to know better given her husband's high- profile job in politics, then tweeted about an ongoing child-abduction case and is now part of an investigation by the Sussex police force into "potential criminal breaches" of reporting restrictions designed to protect victims.
Both Sky News and the BBC (which has been rocked by the fallout from the McAlpine case) have just introduced strict new guidelines for journalists using Twitter.
The BBC has warned its journalists not to break stories on Twitter without first running them past their editors while Sky News has gone further and banned their reporters from re-tweeting news or opinion from any Twitter users who are not employees of Sky News.
It is not just broadcasters who are facing problems with Twitter. A growing number of businesses and high-profile companies have also seen the downside of social media.
Just this week, the UK loan company Wonga had to apologise to Labour MP Stella Creasy after one of their employees used an anonymous Twitter account to launch a highly abusive and personal attack.
Creasy has been a very vocal critic of fast-loan companies such as Wonga, calling them "legal loan-sharks".
A series of tweets aimed at the young MP, calling her (amongst other things) a "nutter", "pathetic" and a "raving self-publicist", were then traced back to an employee of Wonga, who had been using an IP address linked to the company.
Wholly innocent bystanders can often find themselves drawn into a Twitter war. Earlier this month, a charity working on delivering clean drinking water to African villages found itself suddenly and inexplicably under attack from thousands of Justin Bieber fans.
The Thirst Project charity had no idea why it became the target of an avalanche of hate tweets from Bieber fans around the world. These were sent directly to the Charity via Twitter and included such sentiments as "@ThirstProject who wants to help those jungle bunnies anyway?" and "@ThirstProject – Justin Rules – Your (sic) retarded nobody likes you".
It turned out that another tweeny star, actor Drake Bell (who has had a bit of a spat with Bieber) had endorsed Thirst Project.
And for the millions of true Belibers out there, that was enough for them to submerge a charity helping Africans to access clean water under a tidal wave of abuse.
The Thirst Project's CEO, Seth Maxwell, had to make a direct appeal to Justin Bieber, asking him to tell his fans to stop bombarding his charity with hateful and hurtful tweets.
But as Maxwell ruefully acknowledged, more than a week of vile abuse and distressing messages to his charity and those who work for it had "done a lot of damage".
"For days our charity's Twitter feed was hijacked and anyone who searched for us was met with such gross language that I can only imagine what impression it left them with," said Maxwell.
As Twitter stars such as Stephen Fry and our own Ryan Tubridy (both of whom have quit the service because of relentless abuse from "trolls") have found out, social media, with its anonymity and direct access to well known figures, can bring out the very worst in people.
Fry, who makes periodic returns to social media despite the abuse, has often tried to appeal to the better nature of Twitter users, going so far as to draw up a list of suggestions or guidelines for using Twitter, aimed at making it a more pleasant for everybody involved.
Fry says of the people who "troll" or tweet nasty, personal or threatening messages, "they are the kind of people who are themselves so weird and unhappy and lonely and strange, so desperate to be heard . . . talk about get a life!"
Unfortunately, as recent events have shown, appeals for respect, tolerance or just basic common sense will surely continue to be ignored as Twitter and similar social media platforms continue to showcase the best and worst of human nature.