The data-mining feature was available to Zoom users who subscribed to a LinkedIn service for sales prospecting, called LinkedIn Sales Navigator. Once a Zoom user enabled the feature, that person could quickly and covertly view LinkedIn profile data — like locations, employer names and job titles — for people in the Zoom meeting by clicking on a LinkedIn icon next to their names.

The system did not simply automate the manual process of one user looking up the name of another participant on LinkedIn during a Zoom meeting. In tests conducted last week, The Times found that even when a reporter signed in to a Zoom meeting under pseudonyms — “Anonymous” and “I am not here” — the data-mining tool was able to instantly match him to his LinkedIn profile. In doing so, Zoom disclosed the reporter’s real name to another user, overriding his efforts to keep it private.

Reporters also found that Zoom automatically sent participants’ personal information to its data-mining tool even when no one in a meeting had activated it. This week, for instance, as high school students in Colorado signed in to a mandatory video meeting for a class, Zoom readied the full names and email addresses of at least six students — and their teacher — for possible use by its LinkedIn profile-matching tool, according to a Times analysis of the data traffic that Zoom sent to a student’s account.

The discoveries about Zoom’s data-mining feature echo what users have learned about the surveillance practices of other popular tech platforms over the last few years. The video-meeting platform that has offered a welcome window on American resiliency during the coronavirus — providing a virtual peek into colleagues’ living rooms, classmates’ kitchens and friends’ birthday celebrations — can reveal more about its users than they may realize.

“People don’t know this is happening, and that’s just completely unfair and deceptive,” Josh Golin, the executive director of the Campaign for a Commercial-Free Childhood, a nonprofit group in Boston, said of the data-mining feature. He added that storing the personal details of schoolchildren for nonschool purposes, without alerting them or obtaining a parent’s permission, was particularly troubling.