If the victim of cyber bullies doesn’t see the abuse, does that mean it didn’t happen?

That “if a tree falls in the forest”question is one of the approaches Twitter is taking in a multi-pronged war on trolls and Net cowards who hide behind anonymous handles to harass and sometimes physically threaten their targets.

New tools will search for words and language patterns and filter them out of users notifications, the messages Twitter users get when they are engaged or mentioned in tweets.

“We believe that users must feel safe on Twitter in order to fully express themselves,” officials posted on the social media giant’s blog .

“We need to ensure that voices are not silenced because people are afraid to speak up.”

 The company is also defining, and in some ways making more vague, what language makes a tweet cross the sometimes fine line of free speech and abuse.

 And it’s putting in place new rules and verification steps a suspended Twitter user must follow get their tweet privileges back.

 "We are updating our violent threats policy so that the prohibition is not limited to “direct, specific threats of violence against others” but now extends to “threats of violence against others or promot[ing] violence against others.” Our previous policy was unduly narrow and limited our ability to act on certain kinds of threats,” the blog post said.

 The changes come after an introspective OpEd in The Washington Post by Twitter general counsel Vijaya Gadde that acknowledged the challenge of the attempt to bring some more order to the chaos that is social media.

We want Twitter to continue to be a place where the expression of diverse viewpoints is encouraged and aired. To do that, we have to keep Twitter safe for the widest possible range of information and opinions to be shared, even when we ourselves vehemently disagree with some of them,” Gadde wrote.

“Balancing both aspects of this belief — welcoming diverse perspectives while protecting our users — requires vigilance, and a willingness to make hard choices. That is an ideal that we have at times in recent years.”

Company CEO Dick Costolo has been more blunt about the microblog sites’ cyber bullying failure.

 We suck at dealing with abuse and trolls on the platform, and we’ve sucked at it for years,” Costolo wrote in an internal memo that The Guardian says was leaked.

“I’m frankly ashamed of how poorly we’ve dealt with this issue during my tenure as CEO. It’s absurd. There’s no excuse for it. I take full responsibility for not being more aggressive on this front. It’s nobody else’s fault but mine, and it’s embarrassing.”

Some prominent victims agree with him there.

“It’s never too late for social media companies like Twitter to take abuse seriously,” said feminist activist Caroline Criado-Perez.

 A harassment  campaign against her eventually saw the jailing of two people, reports The Guardian .

 “Obviously, we will have to wait to see how these changes get applied in reality, but on the face of it, this looks like a very positive forwards step for Twitter. I’m really pleased to see them taking their responsibility to foster a platform for free speech and debate by creating a platform where people can speak without fear.”