At ABC News we took the decision not to use the sickening footage from a Go Pro feed live streamed by the alleged Christchurch shooter and we chose not to publish excerpts of his so-called manifesto. A few still images from outside the mosques were used.

Most mainstream media made a similar call, though some gave him a platform initially, before pulling back to a more conservative approach.

But we weren't his target audience. All the evidence suggests this was a horrific, cold-blooded, terrorist attack aimed not at the audiences of traditional news organisations but at reaching and triggering atomised and often extreme online audiences.

As has been widely reported, the accused gunman ensured his lengthy treatise was posted online shortly beforehand, he teased the attack and streamed it live, counting on frenetic oversharing to defeat or at least frustrate any attempts by social networks to stamp it out.

His every move appears to have been deliberate, calculated, web savvy and designed to grab attention.

In a brief court appearance, despite being handcuffed, the accused made a sign with his hand that could be interpreted as a message of encouragement for supporters.

The judge had ordered that his face be pixelated or blurred, but he didn't say anything about the accused's hands.

Our journalists in court reported that he'd made the gesture, but we chose not to show it.

This is a fraught area for reporting, particularly as events are unfolding and instant editorial decisions have to be made. We don't always get it right.

There is a legitimate debate to be had about the extent to which showing any disturbing pictures or identifying an attacker gives that person exactly what they want.

But reporting what happened and analysing how it could have happened are clearly in the public interest. It's what responsible journalists do — the test is whether it can be done without giving the alleged shooter the platform they crave.

Once the order to pixelate the accused's face was made in NZ, we chose to follow that direction across our platforms.

Ordinarily a New Zealand judge's jurisdiction doesn't extend across the Tasman, but the digital world we all share doesn't recognise quaint constructs like courtrooms and national boundaries.

An image of the Masjid Al Noor mosque in Christchurch, where the deadly shooting took place. ( Supplied )

International audiences for ABC News are growing, many are Kiwis. As a public broadcaster we should lead in setting standards, so we made a choice.

Other credible news organisations took the same decision.

That word choice here is key.

In ABC newsrooms we make story choices based on public interest journalism and our editorial policies every day and we're rightly held to account for it.

Social media platforms have made some changes to tackle hate speech and violent behaviour, but they could choose to do more. They could set higher standards for removing offensive video and messages.

Free speech is unimaginable without the right to dissent — but commentators, opinion writers and politicians also have choices to make in the example they set.

In the end though it's on all of us — in the news sources we rely on, the social networks we join and what we choose to watch and share.