Upvoted, because the slack part is interesting. Does anyone know what other/replacement communication systems are used internally at Twitter? For my $job, slack is basically where everything happens and if it suddenly disappeared, it would take days for the team to reorganise and probably weeks before I would know how to reliably reach people in other teams. The long tail effects of potentially losing the search history are hard to quantify...

Regardless of everything else happening at the bird site, I'd love to hear how their engineers work through this issue. This is an impressive social experiment!