When Rachel Kremer, 30, a former Zillow saleswoman from Orange County, Calif., filed her complaint, she was not certain “that people would care so much,” she said in a telephone interview. She was surprised to find that her court filing, which alleged that she had been ranked according to breast size, had received graphic photos and had been subjected to “sexual torture,” was soon all over her Facebook feed.

(A Zillow spokeswoman, Katie Curnutte, said Ms. Kremer’s claims “do not accurately reflect life and culture at Zillow, where people work hard and respect one another.” In an email, the spokeswoman added that two of the employees who had sent the messages had been dismissed.)

Next Ms. Kremer started getting supportive LinkedIn messages from strangers, including older women who said they had faced similar situations and regretted not speaking up. “The outpouring of support made me feel like it wasn’t as difficult to continue,” Ms. Kremer said.

For women who feel wronged, the online solidarity can be a valuable tool. “From the plaintiff’s perspective, it’s one of the great equalizers,” allowing women to gain ground against well-funded defendants, said Debra Katz, a Washington lawyer who has been bringing employment and sexual harassment suits for three decades.

But in terms of fairness and resolving disputed issues, “these cases are a mess,” Ms. Katz said. In Zillow’s response to Ms. Kremer’s lawsuit, the company disclosed that she had sent lewd messages to male colleagues — a fact that may prevent a jury from agreeing with her sexual harassment claim, as the judge pointed out in writing.

One day in 2013, Juan Monteverde, a Manhattan lawyer, got a phone call from his shocked wife, who had been emailed a copy of a complaint alleging that he had harassed a younger female colleague, Alexandra Marchuk, at work and coerced her to have sex. He had no idea he was even being sued, but the complaint was soon proliferating online.

“You’ve been accused of something without an opportunity to defend yourself,” Mr. Monteverde said in a telephone interview. The initial legal filings were “just allegations,” Scott Bursor, his lawyer, said in a telephone interview. (No criminal charges were filed.)