Stewart Butterfield and his team at TinySpec had been making a game called Glitch. Slack stands for searchable log of all conversation and knowledge. The fact that it's conversational and searchable is like the two key things about it.
Several People Are Typing was mostly written pre-pandemic but failed to garner publisher interest until a virus locked us all inside our homes with nothing to turn to but our jobs and our friend-Slacks. It manages to perfectly encapsulate what it feels like to use Slack for anything, with a dash of creepypasta for good measure.