There are corners of the internet that are shady and mysterious - you never go there for fear of what you might find.
It is worse if you dare to be noticeably female while exploring them. Your user name, your avatar, anything could lead to unwanted advances, or unwarranted abuse.
A recent survey by Girlguiding, a charity for girls and young women, found that 54 percent of girls aged 11-21 had received some form of electronic harassment, whether receiving sexist comments or having embarrassing photographs of them distributed online.
But online feminist movements are fighting back.
When FemSoc at Pakistan's Lahore University of Management Services heard about a campaign called Who needs feminism, in which people from all sections of society hold up cards reading "I need feminism because…" they decided it would be a good way to spread their message.
FemSoc general secretary DurreSameen Mirza said the group decided to take part in the campaign despite knowing they would receive some negative responses. "We realised that by going public we would open ourselves up to harassment and abuse," she told Al Jazeera "We also realised that this was why the project was important. There are so many misconceptions of feminism and women in Pakistan; we felt it was important to get this discussion started."
DurreSameen said she has received personal abuse and criticism of the campaign, but felt it was essential for the progression of feminism in Pakistan.
When someone sends you a message with such graphic detail about the ways they are going to disembowel you or rape you it does get into your head.
"I have been abused online more than once. The abuse got intense after we launched the campaign," she said. "People would message me on Facebook and Twitter, attacking my beliefs and my character. My initial response would be to engage, but after a certain point you just learn to block these things out.
"In Pakistan, religion is often used to legitimise patriarchal norms and behaviour. When we started our campaign against these norms many people felt like we were attacking Islam."
'Waves' of abuse
When Laura Bates founded the Everyday Sexism Project, she had no idea how quickly it would go viral. She arrived at the idea for the awareness project after sharing her stories of day-to-day harassment and realising that other women had similar tales.
The Twitter handle @everydaysexism gathered followers quickly - including support from female and male celebrities - and the project now operates in 17 countries. The speed at which it grew left Laura unprepared for the backlash that followed.
"It comes in waves," she told Al Jazeera. "They can be quiet for several weeks at a time and then you can get 200 messages very quickly. It is very upsetting psychologically. When someone sends you a message with such graphic detail about the ways they are going to disembowel you or rape you it does get into your head."
Laura was able to cope with the abuse by reaching out to feminist communities online. "When you realise you are not alone, it does make you feel calmer. Because of the way the project is set up, all of the abuse is levelled at me. I think I would find it far more difficult to deal with if it was aimed at the women and men sharing their stories."
Laura told Al Jazeera that she was surprised by how young the girls sharing stories with the project were, with many saying they were harassed while wearing school uniform.
"The education of children has not yet caught up with the accessibility of things online, and I do not think the positive goes hand in hand with the negative," she said.
Laura believes that moderators of sites where harassment is common need to take more responsibility. She said that "what we need is a cultural shift - we are beyond the point that one single piece of legislation can help".
While rape threats are not be illegal in and of themselves, section 127 of the Communications Act 2003 criminalises making grossly offensive or menacing remarks.
The law of online
Professor of Criminal Law Alisdair Gillespie explained that legal jurisdiction is one of the internet's most complicated issues.
"Where the offence is, for example, posting offensive comments then the country where the person is would have jurisdiction," he said. "Where the offence is causing harm to a person then arguably it could be both the country where the offender is and where the victim is located."
Added to this is the fact that something illegal in the UK might not be actionable in, for example, the US.
"In some countries, like the USA, there is no such thing as hate-speech because the right to free speech trumps everything else. In others, such as the UK, the line [between hate-speech and freedom of expression] is more difficult to draw," he said. "Where there is any incitement to violence then that would normally cross the line and anything that is racially offensive would cross the line."
The UK recently held a consultation on social media and abuse in a bid to create some consistency in the way online offenses are delt with.
In many cases, though, the site hosts are under no legal obligation to act, although there may be a moral factor in play.
Mentality of trolling
After Kelly Broderick shared a picture of herself on Twitter with the hashtag #WeAreWhatFeministsLookLike, the image was used as part of a "fat-shaming" meme copied, imitated, and spread all over the internet.
- 40 percent had unkind things said about them
- 21 percent had threatening things said about them
- 20 percent had sexist comments made about them
- 17 percent were sent upsetting photos or content
- 16 percent had embarrassing photos of them sent to others
- 12 percent experienced someone pretending to be them
- Five percent had photos of them of a sexual nature sent to others
Kelly responded by writing an article discussing the lack of support she had received from social media sites where the image was shared. "I found the picture on the Facebook page and went through all of the steps to report the image," said Kelly. "Facebook asked me if the picture was of me and if they had posted it without my permission. I came to find out that because I was an adult living in the United States, they didn't have to do anything about it."
Facebook has previously dragged its feet in removing groups joking about violence against women, while at the same time banning breastfeeding images.
"By the time I realised I wouldn't be able to get it removed, it was everywhere," said Kelly. "I am sure that if someone had told me that if I participated in the campaign, a picture of mine would be taken without my permission and turned into a meme, I probably wouldn't have. But now that I've gone through it and seen that it isn't the worst thing ever and lots of positive experiences can come out of it, I am going to continue to post my picture."
No one who spoke to Al Jazeera seemed surprised that 54 percent of girls had suffered some form of online harassment.
"The anonymity of the internet has made it so easy to treat each other cruelly," said Kelly, "it's no wonder so many girls have been harassed."
Internet psychologist Graham Jones offers some explanations as to the mentality of people who troll online. In an email to Al Jazeera he explained that some forms of trolling could be unintentional.
"The blog post or video triggers some kind of reaction and they fire off a reply. These reactions represent what the individual thinks at that moment," he said. "In the "real world", such reactions - whilst present within the mind of the individual - would not surface.
"The behaviour of others acts as an inhibitory factor. Online those inhibitory effects are not there. People are now seeing what others really think of them. We might call it trolling, but in reality it is a spotlight shining on human behaviour that has always been there, just hidden."
Intentional trolling, he says, could stem from a variety of perceived reasons, including trying to diminish someone they dislike.
"To avoid admitting that someone else may be right means they have to keep acting negatively to "prove" the other person is wrong. But they are only really proving it to themselves," he said. "Intentional trolling incidents is largely down to the psychology of the perception of self.
"Some people are insecure in their self identity and need regular input to help them maintain their sense of self. They do things in order to stimulate that feedback - so they might think they are being humorous when they say something against the campaigners and that feeling is reinforced when others say how funny they are.
"It is all about themselves, not about the victims, who are largely forgotten and ignored by the troll."
Digital journalist and game designer Mary Hamilton told Al Jazeera that there needs to be more accountability online.
"When you are 13 and gaming online and abuse someone, if there are real consequences to that then you are less likely to do it again. Unfortunately that doesn't really happen, so you have people who push it to see how far they can go."
It is all about themselves, not about the victims, who are largely forgotten and ignored by the troll.
Mary has been gaming in one form or another since she was a child, but became a serious online gamer in 2004. With nearly a decade of experience, Mary says she has been fortunate to have avoided any extremes of abuse. "When I was online I would use a male or gender-neutral pseudonym," she said. "I did that because I learnt quickly, as a teenager going into early chatrooms, that you just have to do that to fly under the radar."
Mary is full of positive examples of community management, mentioning Minecraft, which is very popular with young users and which creates a safe online space for children through an active team of community moderators. "In a way I think it is getting better, because now women are more visible online. If this survey had been done in 2004 I would guess that about 90 percent of the girls who used the internet would have received abuse, because it was assumed they weren't there.
"When I shed my pseudonym I didn't receive any gendered abuse, which is something I had been conscious of as a possibility."
Mary does not think that the possibility of harassment should be seen as a barrier to taking part. "If abuse does happen, the person who uploaded the image is not to blame. Blaming someone for putting a picture of themselves on the internet comes from the same mentality of blaming a woman wearing a short skirt for being harassed."
While the situation was improving in some countries, like the UK, there was still an issue of how seriously online harassment was taken.
"Partly this is because it may be easier to prove that they actually intend to do something offline," said professor Gillespie, "and partly because some people still think that the internet is really just harmless. You still hear people saying 'all they have to do is switch the computer off'. You never tell someone who is being stalked 'all you have to do is stay in'."
Follow Philippa Stewart on Twitter: @Flip_Stewart