But now some of the world's biggest employers are coaxing workers to sign up to a new form of social media designed for the workplace. Among the first was Yammer. Then there was Slack. There are also Microsoft's Teams, Google Plus and Facebook's Workplace, adopted by firms including easyJet, Spotify, RBS and Walmart, the world's third-biggest employer.
Conversations that once took place during phone calls, meetings and cigarette breaks now increasingly happen online, meaning they can be shared across offices and time zones. Such systems will be increasingly necessary as more people work remotely.
"Millennials are now going into management roles, and they want to communicate with their employees using the technology they grew up with," says Vicki Huff Eckert, at PWC.
And since many of these apps function well on mobile phones, they can include people such as airline cabin crew or factory workers, who are often culturally separate from head-office colleagues.
Hard evidence about productivity or profit is elusive but many business leaders say they have observed happier employees and better work processes, as well as big reductions in email use. Jen Baxter, at GlaxoSmithKline, says Workplace has helped introverted scientists collaborate in a way that suits them. But there, perhaps, lies a danger.
Slack has been criticised as distracting, an addictive pseudo video game that obliterates employees' concentration by obliging them to reply quickly to the merest of trifles.
"It normalises interruptions, multitasking and distractions," wrote Abe Winter, a tech worker. "[It] will give attention deficit disorder to your whole company."
Another potential problem is what kind of communication such services might encourage.
"The design of the software leads to very different behaviour from people," says Greg Moran, operations chief for Wiretap, a company that uses AI to scan enterprise social networks for abusive or dangerous messages.
"They encourage a chattiness and a back and forth ... the conversational or informal nature of these platforms creates more problematic content."
He points to Uber, which fired its chief executive and 20 other people last year after a former employee detailed sexual harassment she had received over the company chat app. That, in turn, raises the question of surveillance.
They could also be used to root out workers who are planning to leave their jobs or who make negative comments about a boss. For Jamie Woodcock, a sociologist who spent six months undercover in a British call centre, this is just the latest way in which employers are using technology to increase control of workers.
Moran says a debate is required about how much information our society wants managers to have. But if it is anything like personal social media, it could become ubiquitous before that debate even starts.
