Twitter today is awash with people saying goodbye.
The hashtag "RIPTwitter" is trending and lots of the site's users are scrambling to download their data.
They're also sharing alternative places to find them (consumer champion Martin Lewis, who has two million Twitter followers, has set himself up on Mastodon, although he admits he doesn't know how to use it yet).
Twitter's new boss Elon Musk, never one to ignore a trend, tweeted a meme of a gravestone with the Twitter logo on it.
Staff have been leaving in their droves – half the workforce was laid off by Mr Musk one week after he completed his purchase of the platform, and many more are choosing to leave since he sent an email demanding "hardcore" working conditions and long hours from his remaining employees.
Quite a few of those departing, according to their Twitter bios, are engineers, developers and coders – the people who work on the guts of what makes Twitter function.
Let's take the two biggest vulnerabilities that could knock the blue bird off its perch very swiftly.
The first and most obvious would be a catastrophic hack.
Twitter, like all big websites (including this one, the BBC), will be constantly under attack from bad actors – even at state level – wanting to cause mischief. World leaders, politicians and celebrities all have personal Twitter accounts with millions of followers – a low-hanging fruit for a hacker wanting a lot of people to see their scam, as we have seen before.
Or they might just want it to disappear, so they bombard it with web traffic to see if it gets overwhelmed and shuts down that way. Attempts like this will be happening all the time – it's a constant battle.
Cyber-security is, or at least should be, an important part of any 21st Century company's day-to-day operations. Last week Twitter's head of cyber-security, Lea Kissner, left the company. It's not known if she was replaced. (Twitter also has no communications team, so there's no easy way to ask.)
Twitter's security is likely to be pretty robust. You can't run a site used by 300 million people every month that's held together with a bit of string. But that robustness requires continuing maintenance.
Think about your own phone, or laptop, and the regular security updates you have to install. That's because new vulnerabilities are regularly unearthed, new chinks in the armour that you didn't know you had, and it's the job of the provider to send you the fix.
The second potential disaster is that the servers are knocked out – either by someone with a grudge, or by mistake during a routine bit of maintenance that's not properly supervised.
Without servers, there is no Twitter (or Facebook, or Instagram or indeed our digital world.)
Servers – powerful computers – are like the physical bodies of these platforms. They exist in data centres. These are effectively warehouses full of computer servers which are central to the operations of online businesses. The world runs on servers.
As you can imagine, all of those machines generate a lot of heat. Data centres have to be kept cool, and they require a constant source of electricity.
The servers themselves also require maintenance and replacement, as data gets migrated between them. All of that has the capacity for something to go wrong. It would be sudden and dramatic if it did.
Elon Musk knows all this, of course. Let's not assume that he doesn't. However he may choose to play the buffoon.
We don't know who is currently keeping watch.
But something happened to me yesterday that made me think perhaps there are more people at Twitter watching than we think.
I told the story about an astronomer who was locked out of her account after wrongly falling foul of automated moderation tools. Nobody at Twitter or Mr Musk's other firms responded to me, or made contact with her. But her account was indeed restored later that day.
Somebody, somewhere inside Twitter, was paying attention. Perhaps there are still enough of them who are doing just that.
There is of course a third option – the nuclear one – which is that Musk declares Twitter bankrupt, and it gets wound down. Although right now he seems to be enjoying his status as Chief Twit.
You can follow Zoe Kleinman on Twitter (@zsk), as well as on Mastodon (@email@example.com).
Musk completes his $44bn (£38.1bn) takeover of Twitter, immediately firing a number of the company’s top executives and tweeting “the bird is freed”.
Before officially taking charge of the company, Musk changed his Twitter profile to read “Chief Twit” and turned up to Twitter HQ in San Francisco carrying a sink, saying: “Let that sink in!”
Musk responds to concerns that he will loosen regulations at the company governing hate speech and misinformation by saying he’s “not yet made any changes”. He adds that a new “content moderation council with widely diverse viewpoints” will meet before any policy changes.
After a surge in tweets containing racist language, Twitter’s head of trust and safety says: “Hateful conduct has no place here.” Yoel Roth says the company is taking action against users “involved in this trolling campaign” to make Twitter safe and welcoming for everyone.
Musk tweets an article containing a number of inaccuracies about an attack on the husband of US House of Representatives Speaker Nancy Pelosi by a hammer-wielding intruder. The site has a history of publishing inaccurate stories and Musk later deletes the tweet after a backlash.
With just over a week to go before the US midterm elections, Musk responds to questions about whether he will reinstate former President Donald Trump’s account on Twitter by tweeting: “If I had a dollar for every time someone asked me if Trump is coming back on this platform, Twitter would be minting money!”
Later that day, Musk attended a halloween party in New York and posed for photographs wearing a “Devil’s champion” costume.
Following reports that Twitter will begin charging users to have verified accounts, Musk responds to criticism from author Stephen King by saying: “We need to pay the bills somehow!”.
Employees at the company begin receiving emails entitled “Your Role at Twitter” informing them whether they have lost their jobs. Responding to news about the layoffs, Musk says “unfortunately there is no choice when the company is losing over $4M/day”.
Yoel Roth, the head of trust and safety, said 50% of the company’s nearly 8,000 employees had been laid off but sought to reassure users and advertisers that the platform’s moderation capacity remained intact.
Twitter co-founder and ex-CEO Jack Dorsey breaks his silence over the Musk takeover to apologise to staff who have lost their jobs, saying: “I own the responsibility for why everyone is in this situation: I grew the company size too quickly.”
Musk announces that Twitter accounts impersonating people without being clearly labelled a parody will be permanently suspended – a change to the previous process when accounts were given a warning first.
A number of accounts that changed their name to “Elon Musk” and mocked the billionaire had already been suspended or placed behind a warning sign.
In his first email to Twitter staff, Musk warns that the “economic picture ahead is dire” and adds: “Without significant subscription revenue, there is a good chance Twitter will not survive the upcoming economic downturn.”
Meanwhile, after the launch of the $8-a-month Twitter Blue subscription, which gives paying users a blue tick, a slew of parody accounts that appear to be verified emerge, including a fake George W Bush account that tweets: “I miss killing Iraqis”.
More high-profile staff quit, including head of trust and safety Yoel Roth and chief security officer Lea Kissner.
The option to subscribe to Twitter Blue disappears after its initial bumpy roll-out. Musk later confirms that the launch of the service has been put back to the end of November “to make sure that it is rock solid”.
Reports in US media say thousands of contractors who had been working for Twitter have had their contracts terminated. Technology news site Platformer says as many as 80% of its 5,500 contractor workforce were laid off in the move but the company made no official announcement.
In a late-night email to all Twitter staff, Musk says employees must commit to a “hardcore” culture of working “long hours at high intensity” or leave the company.
In a surprise announcement, Twitter says its company offices will be closed temporarily. The move comes amid reports that large numbers of Twitter staff had resigned.
Responding to fears the platform was about to shut down due to losing key staff, Musk tweeted: “The best people are staying, so I’m not super worried.”
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Twitter today is awash with people saying goodbye.