There is plenty, google it. Here are a few articles of the top of my head.

http://time.com/4457110/internet-trolls/

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Twitter has it the worst:
>Vijaya Gadde, Twitter's top lawyer, has admitted that the company has been "inexcusably slow" in fighting off the kind of vicious online abuse we saw in the Gamergate scandal, in which video game fans send rape and death threats to women who suggested that some games featured sexist portrayals of women.

>On the same day, a study of 134,000 abusive social media mentions showed that 88% of them occur on Twitter. Only a tiny fraction of online abuse happens on Facebook or other social media.

http://www.businessinsider.com/statistics-on-twitter-abuse-rape-death-threats-and-trolls-2015-4?r=UK&IR=T&IR=T

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This isn't something that happens to women only either, sometimes it gets really dangerous for the streamers.

https://www.youtube.com/watch?v=4RqFjJGfrFo

Not to mention the "trend" lately of SWATing streamers live and calling local places where they are located and getting them in trouble in many ways. This streamer that I have been following for quite a while lately was banned on Twitch because his viewers kept trolling him, the latest was sending a SWAT team to the airplane he was boarding.

https://www.youtube.com/watch?v=CNpxQ6ksYy8

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The internet is full of this. In my eyes this platform is one of the safest ones from troll abuse currently and I hope it remains that way.