Edward Snowden fled to Hong Kong, where he worked in cloak and dagger secrecy with a team of journalists to pore through the data, before publishing it on newspaper front pages.

When Jack Teixeira allegedly decided to leak classified information, he just posted it in his gaming group chat on Discord, to impress his online friends. And there the documents stayed for weeks, apparently unnoticed.

Then, they went viral.

The Discord leaks show the difficulty of keeping secrets in an extremely online world - and how quickly they can spread.

Perhaps Teixeira was counting on the nature of Discord itself, which is made up of thousands of small, closed groups. It's notable that this wasn't a leak posted to social media that, amplified by algorithms, immediately went viral to an audience of millions.

It was passed from small Discord chat to bigger Discord chat, through bulletin-board 4chan and messaging app Telegram and then onto Twitter and the wider world.

Teixeira seems to have assumed the documents would stay where he posted them - the group was a "tightknit family", according to one member interviewed by the Washington Post.

When the leaks went public, he was "frantic".

You don't need powerful algorithms and population scale audiences to go viral, though: it's how things used to work before the social media giants. If something is compelling enough, it will get shared.

The leaks obviously raise huge questions for US intelligence. It is hard to patrol a platform like Discord. Unlike Twitter or Facebook, the site relies on users to moderate their own servers - as a result, the content is often wildly offensive (the members of Teixeira's group allegedly shared racist memes and jokes). Members have to be invited.

But security agencies have long been aware of gaming forums' potential for espionage. Writing in the Economist, the intelligence expert Thomas Rid says: "Preventing unauthorised disclosures is hard, and the risk can only be managed, not eliminated." Still, the US intelligence establishment dropped the ball badly, he argues. "The government should work harder to prevent leaks," Rid writes. "It should also punish leakers harshly to deter imitators."

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Counter intelligence focuses on finding whistle-blowers and spies who are trying to stay hidden. Perhaps the US government was surprised by the idea that someone might post classified information just for internet bragging rights.

Teixeira appears to have been more than naïve about the consequences.

Snowden understood what he was doing. Teixeira did not. Another difference: Snowden was never apprehended by the US; Teixeira is in custody. Having failed to prevent the leak, the US is likely to follow the other part of Rid's advice and punish him harshly.