Rank-and-file employees were more likely to share concerns about the new era of office chat. There was the woman who cited a “truly unhinged Slack situation” — dozens of new rooms serving a workflow that seemed only to make sense to the new boss — as one reason she ultimately left her job at a major media company. There was the guy who told of an ambitious new employee at his firm who spent his first weeks scouring thousands of Slack logs dating back years before his arrival. “He has an encyclopedic knowledge of why certain decisions were made and every personnel thing that ever happened,” the employee said. “Every little interpersonal tiff. Every interview we ever conducted!”

There were the new employees themselves, who made the mistake of searching for their own names on their first days. (The venture capitalist Hunter Walk coined a term: “Slackenfreude,” which he defined as “the joy in knowing that as a Slack group grows, the likelihood of a new member searching their name and finding they’ve been slagged on in earlier conversations reaches 99.9 percent.”)

Most common were mixed feelings, often related to privacy and productivity. “We’ve had to consciously discuss using Slack less often,” said Lacey Berrien, who works at marketing start-up Drift. “I had our I.T. team check a few weeks ago, and we were up to over 950 Slack channels,” she said, “and that doesn’t count the private ones.” (The company C.E.O. recently told employees, via email, “Instead of an endless back and forth in Slack trying to get my point across I am just having a real conversation when convenient.”)

Stephanie O’Quigley, a public relations professional in New York City, said her colleagues were not at all reluctant to pick up Slack — which turned into a problem. “Slack was used to try and alleviate the divide between different departments in the company, and we hoped it would make us more cohesive as a company,” she said in an email. “People were constantly chatting via Slack, and with work-from-home employees, conversations via Slack ended up taking much longer than a phone call would.”

[What if all your Slack chats were leaked? Hmm?]

Slack also defies the social customs and expectations of email, codified over decades of use and misuse. Some employees — and, crucially, employers — are still learning how to establish rules and boundaries around real-time chat. “I personally felt so much anxiety over Slack,” Ms. O’Quigley said. “I love my job, but nothing triggers alarm bells like when you receive a message from your team or boss after work hours.”

When Anil Dash took over as the chief executive of Glitch, a software development platform, the company had already largely moved on from email, and had been organized around group chat applications for more than a decade. “It was interesting to come into a company with 10 years of practices and zero internal notes,” he said. There were all sort of customs, if not rules, about how to behave, what was expected, and simply how things worked. A room where employees would announce their arrivals, daily, with morning emojis; rooms where everyone read but few posted; rooms where everyone posted but few were expected to fully read. (The solution? A shared, editable company handbook, outlining expectations and practices where possible.)