'm Rachel Martin, and this is For The Record.

When you live part of your life online through social media, you have to be prepared for everything that comes your way. The more visible someone is, the more likely a target of harassment. And on Twitter or Facebook, that harassment can sometimes be frightening. For The Record this week - the disturbing cost of a life online. And a warning - some of the descriptions in this story are violent.

All you have to do is peruse the comment section on a news story to know it doesn't take much for some people to get nasty fast. Just last week, the Reuters news agency announced it is shutting down public comments on its news site. Even subjects that don't seem controversial can bring out the worst. After the comedian Robin Williams died, his daughter received all kinds of negative messages about her father's suicide.

UNIDENTIFIED WOMAN #1: Zelda Williams, who used Twitter to pay homage to her father after his death, was announced, has abandoned her Twitter and Instagram accounts. Her final tweet read...

MARTIN: Last month, MSNBC host Melissa Harris-Perry decided to stop re-tweeting. (SOUNDBITE OF ARCHIVED RECORDING)

MELISSA HARRIS-PERRY: ...Because I fear that I would send all of my harassment that comes to me over to some person who doesn't deserve it.

MARTIN: According to a recent study by the Pew Research Center, 40 percent of Internet users have experienced some kind of harassment. Most of that is happening on social media. And the people who get the really bad stuff are women. Here are three of them.

MIKKI KENDALL: Mikki Kendall from hoodfeminism.com. I am an occasional feminist, a cultural critic and sometimes an Internet loudmouth.

BRIANNA WU: My name is Brianna Wu. I'm head of development at Giant Spacekat. I make sure our software is being engineered on a timetable.

DR. DANIELLE LEE: I am Dr. Danielle N. Lee. I am a biologist at Cornell University. I examine both the basic behavior as well as individual differences in behavior of the African giant pouched rat.

MARTIN: (Laughter) It's a very specific line of work.

LEE: It is a very specific line of work.

MARTIN: Each of these women work in very different industries - media, tech, biology. But they each have very active lives on social media where they engage on everything from issues specific to their field to the big news event of the moment. For Danielle Lee, a black scientist, she says the Internet helps her break down stereotypes.

LEE: I really like being in public. I really like sharing science with people. That's why I'm online.

MARTIN: For Mikki Kendall, it's just part of her job.

KENDALL: I'm a writer. Financially, I can't afford to not have some kind of a life online because part of getting paid is people knowing who you are.

MARTIN: And Brianna Wu - she skipped the description of how she uses the Internet and instead launched right into how it has brutalized her. How would you describe your online life?

WU: A war. I mean, I wish there were a different way to say it, but the last month has just been - it's frankly been horrible.

MARTIN: Wu is one of several women embroiled in an online saga called Gamergate.

WU: Gamergate is basically a group of male videogame players that are - they're frustrated with the inroads women are making into the videogame industry. And so I posted this image that was making fun of them. And 24 hours later, I'm fleeing from my home because people had threatened to kill me.

MARTIN: Mikki Kendall, the writer, got equally frightening threats. Three years ago she wrote a first-person story about getting an abortion - a story she knew would be controversial. Still she wasn't prepared for the backlash.

KENDALL: People threatened to shoot me. People threatened to gut me. There was a guy who told me he would cut me open and make me sure I never got a chance to kill another baby.

MARTIN: She dismissed most of it until the threats were no longer restricted to the digital world.

KENDALL: I got an actual picture sent to me of me and my children walking across the parking lot of the apartment complex we lived in. And I don't know how close this guy was, but the message was very clear.

MARTIN: The police intervened and eventually the man was apprehended for another crime. But you don't have to get death threats online to feel harassed. Danielle Lee, the biologist, starting getting attacked after writing about the shooting of Michael Brown in Ferguson, Missouri this summer.

LEE: So someone had found a picture of me next to an animal because there's a lot of pictures of me next to animals. And they took that picture and then they made comments about what do you do with, essentially, whining black people? You shoot them. And I shut my account down after that.

MARTIN: Two weeks later, she was back online. She and the other women we spoke to all agreed that quitting the Internet isn't an option. For Mikki and Brianna, the abuse got so bad, they went to the police. But for most, the first line of defense is to block the user which is clearly Danielle's tool of choice.

LEE: I will put the brakes on that in a minute. I will - my block hand is strong. I will block you in half a minute. I'm like wax on, wax off with this block hand.

MARTIN: A lot of the harassment we've been talking about - most of it, in fact - happened on Twitter. The company recently partnered with a nonprofit to launch a new reporting tool to track bad online behavior. Twitter told us when they find out about content that's violating its rules, they shut the accounts down. Mikki Kendall said that's good, but harassers, also known as trolls, often use an easy workaround.

KENDALL: Well, what trolls will do is then just make a new account. Right? And IP blocking, in theory, could work if you blocked an entire IP address, except the reality is that most of them are savvy enough to spoof their IP. And then your IP will look like you're from Croatia when you're really in Kentucky.

MARTIN: All three of these women kept up their online profiles after the harassment. So have they decided this is just the price of a life online?

WU: If you're a woman in the videogame industry, sadly, getting death threats and rape threats is part of your job. I've been getting these for quite a while now.

MARTIN: Mikki Kendall says she doesn't expect the Internet to be a nice place. She even admits to stirring things up on purpose from time to time.

KENDALL: You know, I am not everyone's favorite cup of tea. There are people who will tell you that I am a stinky, mean girl. I don't necessarily listen to them when I say it, but I am certainly happy to protect their right to continue to think I am a stinky, mean girl, as long as they stop at stinky, mean girl and don't start with I'm going to find where you live and rape you.

MARTIN: Each of these women have made some life changes because of the abuse. Danielle simply shut down her Twitter account for a couple of weeks. For Brianna and Mikki, the threats were more severe. They both moved out of their homes. And Mikki thought about changing careers altogether.

KENDALL: And we talked about it as a family. I made the offer to my family. I've been a secretary before. I could go be a secretary again - that kind of thing. And they said that that wouldn't be right, and that wouldn't be fair. But that they did want us to make some changes. And we made those changes.

MARTIN: One big change - whenever she does public appearances now, she employs a real-life protection mechanism to those digital threats.

KENDALL: Chances are good, if you look around the room, you'll see at least one 6 foot tall, really broad shouldered black guy standing there looking at you. That's my husband. He's at everything.