Missing from that list: last Friday there was a huge hackathon in Germany that tried to create a slack project and invite around 45k people to it, which totally crashed the project.
The hackathon organizers said they were in contact with Slack's CEO or CTO (cannot remember which one), and they continued trying to add people over most of the weekend.
They were in contact with the CEO. They had some problems since they wanted to send out an email to all 42k participants with an invite link. Apparently invite links for Slack are only valid for up to 2k users.
It seems like the Slack team was able to help, but they didn't disclose how exactly [1].
Exactly that. It was a nightmare. I wanted to participate and it was a disaster. Channels were an unmoderated mess. Lots of people just used it to advertise whatever solution they are currently selling and many people just were not able to find projects they could help get off the ground.
I believe the government will pat itself on the back as will do the organizers, but having lived through it and genuinely tried to help people I can only count it as one of the worst wastes of time I ever experienced.
Sadly, because the idea behind it was totally great. And I believe if a team already had formed before that, that they could achieve interesting results. But going in and trying to just be help- and impactful was doomed.
Sure, there are large slacks, but those aren't those for a lot of working groups, and announcements, and basically just being there (like IRC)? Whereas for a hackathon you would need to talk/interact with those who are on your team. And that team can just use whatever they want? (Skype, matrix/riot, hangouts, fb messenger, and of course slack too.)
The hackathon organizers said they were in contact with Slack's CEO or CTO (cannot remember which one), and they continued trying to add people over most of the weekend.