Hello and welcome to the intelligence on Economist Radio.

I'm your host, Jason Palmer.

Every weekday, we provide a fresh perspective on the events shaping your world.

While gun deaths have dropped dramatically in big American cities such as New York and Los Angeles,

the murder rate in Chicago has remained stubbornly high, spiking in 2016. A new program is working

to reduce the violence by drawing lessons from West African research. And once upon a time, in lands far, far away, there lived kings and queens.

Lots of them.

These days, there are far fewer monarchies in the world,

but stories like this weekend's coronation of Thailand's new king are big news.

What made so many monarchies disappear,

and what's to be learned from those there left?

But first, in 2005, when YouTube was new, there wasn't much to see, mostly home videos, Pratt Falls, and a few intrepid video bloggers.

Since then, it's become the free television service for much of the world. Now it's owned by Google, and more than 2 billion people visit the site at least once a month.

The volume on offer of entertainment, education, information,

and, well, wasted time, is hard to fathom.

It would take 100,000 years to watch all of it.

But with YouTube's incredible growth

have come the challenges of moderating the dark side of its content.

Susan Wicheski got the first message about the New Zealand Massacre not long after it began, around 8pm at her home in Northern California.

Gotti Epstein is our media editor.

So the assaults on two mosques in Christchurch had

begun maybe 15, 20 minutes earlier. The shooter had live streamed the killings on Facebook,

...