From the Intelligence, I'm Jason Palmer. This is Episode 5 of a new 8-part podcast series from the Economist.

The show is called The Prince, and it's about the leader of China, Xi Jinping.

If you haven't heard the previous episodes, or if you can't wait for the next one,

you can hear the whole series now by searching for The Prince on your podcast app.

As a young guy, Eric Liu had a huge responsibility. He controlled what people saw on the Chinese Internet.

If you think it's bad, get rid of it.

He was a sensor for one of China's biggest social media companies.

I joined Weibo in March 2011.

Weibo is China's version of Twitter, but with an army of sensors, racing against its users to make sure online content is acceptable to the Communist Party.

It's really hard to keep up with the pace of the world.

All sensitive words are singled out by the system, unhighlighted in orange, or red for more sensitive ones.

The sensor needs to decide in a split second whether the sensitive words have been correctly identified.

The team leader would assign Eric, say, every post between 104 and 1008 AM.

That would take Eric's whole shift, a full 11 hours.

It makes me feel like I'm just working on a factory line.

It's a physically very tiring job.

I remember very few staff were over the age of 30.

There were about 120 people in the team at the time.

Of course, that's extremely small, even to the point of being unthinkable now.

Millions of people are employed by China's censorship machine.

The number of internet users has skyrocketed, and the list of words deemed sensitive is always changing.

Depending on what's trending online, even words that seem innocuous, like walk or disagree.

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