Since October, advertisers have been riveted by an anonymous Instagram account called Diet Madison Avenue, which solicited reports of sexual misconduct in the ad industry and published the names of alleged harassers. But now, the account has been deleted and its creators’ names could be made public through a defamation lawsuit brought by a man who claims Diet Madison Avenue posted false allegations about him that cost him his job.

The suit has put a spotlight on the new digital forums, like Instagram accounts and Google spreadsheets, that have been used to surface allegations of harassment in the #MeToo era and have highlighted the precariousness of maintaining anonymity online.

Diet Madison Avenue, which said it was run by 17 people, urged those who worked in advertising to send their stories of harassment, promising anonymity and offering resources to victims. Through Instagram Stories, which disappear after 24 hours, the account called out agencies and published the names of more than a dozen alleged harassers. Several agencies dismissed men whose names appeared on Diet Madison Avenue.

The account’s snarky tone — photos of some the accused were manipulated so that the men appeared to have pigs’ noses — had a polarizing effect. Many people, particularly younger workers in the advertising industry, lauded the account for exposing the misdeeds of powerful men, but others said it was tantamount to trial by social media. The account had more than 20,000 followers before it was deleted last month. (Another version has since been created but it has only 1,200 followers.)