Mark Zuckerberg has ignored the Prime Minister's request for him to attend the Christchurch Call summit in Paris.
The Facebook CEO will be a no-show, instead sending a lower level representative.
Twitter is sending its top boss, who'll join world leaders including the UK, Canada, France and New Zealand to tackle the damaging role social media played in the Christchurch terror attack.
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Zuckerberg is the world's most powerful social media giant, but will snub the Paris event despite Facebook livestreaming the Christchurch terror attack, exposing more than a million people to the slaughter - including children.
Jacinda Ardern denies it's a snub to New Zealand.
"Would it have been preferable to have him there? Absolutely, but what I think is ultimately key is that Facebook joins this call to action."
Zuckerberg's famous lieutenant Sheryl Sandberg is a big fan of Ardern, but not big enough to get her to Paris either.
"It would be much more disappointing if they didn't engage at all and if they chose not to sign," Ardern says.
Facebook's sending the UK's former Deputy Prime Minister Nick Clegg, who is now head of Facebook's global affairs.
Twitter's making more of an effort. Its eccentric CEO Jack Dorsey takes daily cold baths and barely eats - but he'll be there.
Ardern says the ball is in the court of the social media giants.
"I need to leave it to the leadership of Facebook to set out its view on the response to the call to action."
She's refusing to defend Facebook's snub, instead celebrating those that can make it - leaders from the UK, Canada, Ireland, Norway, Jordan, Senegal, the EU and France.
German Chancellor Angela Merkel wanted to go, but can't.
"I'm pleased at the response that we've had regardless of the availability," Ardern says.
Internet New Zealand's boss Jordan Carter will be in Paris chairing the warm-up act the day before the Christchurch Call.
"I hope that the companies and governments can get a deal together because we need to have change in this area," he says.
"Ultimately we saw a massive failure that I think everyone, tech companies and government are keen to address," Ardern says.
There's another glaring omission from the line up - no Donald Trump.
The US President is the only leader from our Five Eyes spy club who is not going.
He's also one of the world's most prolific and infamous users of social media who's currently fuming about social media censorship, worried about a crack down on freedom of speech.
While Ardern is disappointed Zuckerberg's not coming, the absence of The Donald is probably more welcome.