When Dean Dunbar learnt gruesome and pornographic photos had been posted on a tribute page dedicated to his teenage son Joseph and the other 28 men who died in the Pike River mine blasts, he felt pity.
"I guess if they are that way and are that incompassionate and that backward-thinking then I guess I feel sorry for their children," he said.
"They hop off that computer after giving themselves a thrill or whatever drives them. Hopefully they haven't got children under their roof."
Amid the tributes to lawyer Greg King following his death last Saturday were messages devoid of sympathy.
"Karma", tweeted one person. Other defamatory comments were swiftly removed from messageboards.
Facebook tribute pages for murdered Auckland teenager Emily Longley were pulled after they were defaced with lewd photos and nasty comments.
And across the Tasman, celebrity ex-pat New Zealander Charlotte Dawson was hospitalised after a torrent of abuse from Twitter trolls.
The hate campaign included death threats and calls for the 46-year-old TV presenter to "stick your head in a toaster" and "kill yourself".
The relentless abuse got too much. Dawson told the media she was "pushed to the very brink by these creeps" before recovering and unmasking some of those responsible.
Trolling is generally defined as posting obnoxious, abusive or simply distracting messages or images to provoke a response. And it's on the increase.
Police say staff are dealing with a growing number of complaints from people who have been "intimidated, bullied, harassed and threatened on the internet".
Independent research suggests as many as one in 10 New Zealanders have experienced harmful communication - and the rate more than doubles among 18 to 29-year-olds who are the heaviest users of new media.
New Zealand laws provide only limited protection against communication that causes mental distress if there is no physical threat.
But in August the Law Commission released its report on Harmful Digital Communications with recommendations on how to deal with a practice linked to self-harm and suicides, accompanied by a draft bill.
Among the recommendations in the report is the introduction of a new offence targeting digital communications that are "grossly offensive or of an indecent, obscene or menacing character - and which cause harm".
Material posted on websites, message boards, blogs, social media sites, emails and texts would be covered under the proposed law.
The report is now with the Government, and Justice Minister Judith Collins is expected to make a decision on possible changes next year.
Law change is one way of dealing with the "horrible, heinous, vile" practice of trolling, but there needs to be more public debate and education around online ethics, says Auckland University Department of Film, Television and Media Studies senior lecturer Dr Luke Goode.
He says trolling should also be looked at in a broader context.
In a climate of global recession social media has provided "one more outlet for people to engage in hateful speech in a particularly cowardly way because they usually hide behind anonymity", he says.
"I can't help but think at least we shouldn't separate what's going on online from that wider context. I think it's too easy to just look at this stuff in terms of pathological individuals. It's about individuals but it's also about a wider social climate that we've got at the moment."
If the global recession is a concern, so is global reach.
The nature of cyberspace means trolls can target people anywhere.
When "inappropriate and disturbing" images of dead Canadian teenager Amanda Todd - whose suicide was attributed to cyber-bullying - were posted on her memorial page, it sparked widespread outcry. Specialist cyber crime teams traced the posts to New Zealand, where some were found to have been posted by Raglan 17-year-old Corey Hartstone.
He and his family were spoken to by police, the images removed and his Facebook account shut down.
Little more could be done.
"Trolling, or posting inflammatory/disruptive comments, while offensive to some people will not necessarily be an offence in law," said a police spokeswoman, who advised victims to take screen shots of offensive material. "It depends on what is said and the circumstances."
Hartstone didn't upset everyone though.
A 19-year-old troll traced by APNZ and known online as "Thaddeus Cyburverminn Trohll" accused Hartstone's critics of trolling of their own.
"They were quite hypocritical if you ask me, like they were telling Corey (on his profile page) to kill himself.
"They were telling him to drink bleach. All this terrible stuff, man."
Cyburverminn - who offered to supply a photo but didn't want his real name used - spends at least 10 hours a week posting deliberately obnoxious and extreme messages to provoke a response when something catches his interest.
The payoff is entertainment, he says. "We do it for the laughs. We do it for reactions."
Nothing appears to be off-limits with anything from politics, religion and race, to appearance, music and grammar providing a rich hunting ground of material.
"I just leave a comment, look for a reaction, laugh at it and move on."
Does Cyburverminn think about the possible devastating effects his trolling could have on families who have lost loved ones?
Does he care?
"No. I've never done anything so severe that it would cause someone to kill themselves. Mostly they aren't offended and just laugh."
Most trolls tend to be male, but beyond that there seems to be no typical exponent.
In Ireland, writer Leo Traynor and his wife were targeted for more than three years. He was called a "Jewish scumbag", flooded with disgusting images of concentration camps and corpses, abusive emails, and sent a box of ashes with the note "say hello to your relatives from Auschwitz", The Guardian reported.
He told authorities and, with the help of an IT expert, traced the source as a friend's 17-year-old son.
Back in New Zealand, trolling is a fast-emerging trend that needs to be stamped out, says NetSafe director Martin Cocker.
Education helps and the proposed law change is "a great idea", he says. "It's one of those things that you see happening in other jurisdictions and know that it will emerge here."
Tips for reducing risk
* Be wary what information about yourself and others you put online
* Don't feed the trolls - don't get into an exchange with them
* If you're targeted by a troll, take away their power by removing the posts
* If you're being targeted, let someone know
* Parents should take children's concerns seriously