In 2007, I began a PhD thesis entitled: "Trolling in computer-mediated communication: impoliteness, deception, and manipulation online." Six years and countless high-profile trolling incidents later, trolling has become all too common.

Many of us have a working idea of what trolling is – causing mischief online for fun. But fewer of us realise that trolling comes in a wide variety of flavours. A small handful of those in my research include RIP trolls, who spend their time causing misery on memorial sites; fame trolls, who focus all their energies on provoking celebrities; care trolls, who purport to see abuse in every post about children or animals; political trolls who seek to bully MPs out of office; and many others besides.

Moreover, trolls don't simply spew vile tirades of abuse. In fact, the data repeatedly shows that such obvious trolls are easier to deal with. When someone pours forth unprovoked hatred, there is really only one interpretation: they're aiming to manipulate your feelings (eg to hurt you) or even your behaviour (eg to delete your Twitter account). However, such attempts are so painfully obvious that they are easy to identify, block, and if serious enough, to prosecute.

Where we need greater understanding is in the world of covert trolling. This craftier breed is neither obviously hateful, nor openly offensive. Instead, these trolls live in the twilight between what we think their intentions are, and what they really intend. The fact is that we never know another person's intentions. We are only ever guessing, based on the evidence they present us with, and a crafty troll will present just enough evidence of being credible that to block them would seem like a dangerous step towards infringing free speech. Such trolls will even use this defence, and accuse those who block them of cowardice, censorship, and losing the argument. The average individual is left stuck between doing the morally upstanding thing (upholding free speech, engaging in a debate) and the wise thing (protecting their own peace of mind).

In short, while obvious trolls are an unsophisticated hammer on the nerves, covert trolls are the insidious, fine-tuned torture of doubt and misery. These are the trolls whose behaviour is most difficult to capture under current legislation (and indeed, some free-speech activists would argue that their behaviour should not be captured), yet they are also the type that, for the ordinary user, can be most damaging. The most common question I get now is, "How should I deal with trolls?"

The next stage of my research presents the major response methods that ordinary individuals use, and the risk/effectiveness of these strategies. Between now and then, however, there is still much work to be done, and not all of it involves researchers in labs processing giant banks of data. A crucial part of it involves a change in attitude.

Perhaps the most disheartening aspect of my research is the general view – not just socially, but legally and politically too – of online misbehaviours and crimes. Trolling is yet to be widely accepted as involving "real" perpetrators, "real" victims, or "real" harm. It's "just the internet" and "you can switch it off". While telling a woman not to leave the house at night if she doesn't wish to be raped would attract general contempt and disgust, it still seems to be perfectly acceptable to tell individuals not to go online if they don't wish to be trolled or cyberbullied. Further, trolling is only one phenomenon in the spectrum of online misbehaviour and crime, from the predatory (cyberbullying, cyberstalking, online grooming) through to the fraudulent (catfishing, e-hoaxing, Münchausen-by-internet). Like trolling, these are frequently viewed as unreal or, at best, inferior versions of their offline counterparts.

To even begin to understand and tackle these behaviours, we need cutting-edge research hubs, like Lancaster University's ESRC-funded Corpus Approaches to Social Science centre, which supports major research and projects similar to those I am involved in. More fundamentally, though, we need to see a change in attitude – socially, legally, and politically. The internet is arguably the most influential and ubiquitous technology of our time. For many of us, it is central to our lives, and we cannot be content with the idea that it is "real" and important when it is beneficial, but "unreal" and unimportant when it throws up difficult problems. In short, if we are to realise the internet's full potential for good, we must start taking seriously the many ways in which it is used for harm.