Samuel Hulick identifies Slack as a platform that is neither asynchronous or synchronous. It’s asynchronish. He argues the results of this are not pretty:
At first I thought this sounded delightful — it would be the best of both worlds! I was always free to drop someone a line, and if they were feeling chatty, a full-fledged conversation could simply spring up, with no need to switch platforms.
After getting to know you better, though, I’ve found that your “asynchronish” side is less impressive than I first thought. It leads to everyone having half-conversations all day long, with people frequently rotating through one slow-drip discussion after another, never needing to officially check out because “hey! it’s asynchronous!”
In an asynchronish environment, you’re always checked in, and discussions never end.
But you can check out when you need to, right? Hulick argues that this is not possible, because decisions that impact you can be made at anytime:
This is awesome for speeding up the tempo of company directives, but it also places a ton of pressure on everyone involved to maintain even MORE Slack omnipresence; if any discussion might lead to a decision being made, that provides a whole lot of incentive to be available for as many discussions as possible.
As such, Slack gives power to the people who can afford to stay on Slack and takes power away from those can’t.
Hulick suggests some changes that could mitigate the issue (autoresponders, Do Not Disturb statuses, etc), but there may be a flaw in the very heart of the asynchronish model.
Amber Case argues that technology should interrupt us only when there is action needed. See Tea Kettle Tech
These issues fall into an area of psychology called human factors. Here is a textbook treatment of Human Factors Psychology and Workplace Design.