Workplaces have adopted internal social tools—think stand-alone technologies such as Slack, Yammer, and Chatter, or embedded applications such as Microsoft Teams and JIRA—at a staggering rate. In an ambitious study of 4,200 companies, conducted by the McKinsey Global Institute, 72% reported using them to facilitate employee communication. That figure grabbed our attention, so we asked leaders of both large and small organizations for more insight into why they were turning to social tools and platforms. They said things like “Other companies are, so we should too” and “That’s what you have to do if you want to attract young talent.” Although the bandwagon effect was not a surprise, this was: Few of the rationales were based on a solid business case, which leaders normally require when considering other technologies, such as CRM software or computer-simulation tools.

A version of this article appeared in the November–December 2017 issue (pp.118–126) of Harvard Business Review.