Yelp Inc. can’t shield the identify of an anonymous reviewer who posted allegedly defamatory statements about a tax preparer.

The ruling Monday by a California state appeals court is a setback for websites in an ongoing battle to protect their users, as well as their own businesses, from lawsuits they say are preempted by free-speech rights.

Alphabet Inc.’s Google, Facebook Inc., and the Electronic Frontier Foundation backed Yelp in its bid to overturn a judge’s order requiring it to reveal the identity of the accountant’s unhappy client. The online review said the tax preparer had prepared a sloppy return for double the money he initially quoted.

The three-judge appeals panel in Santa Ana agreed with Yelp that it could protect the First Amendment rights of its anonymous reviewer but it still had to turn over the information. The panel reasoned that the accountant had made a showing that the review was defamatory in that it went beyond expressing an opinion and allegedly included false statements.

San Francisco-based Yelp declined to comment on the ruling.

The case is Yelp Inc. v. Superior Court of Orange County, G054358, California Court of Appeals, Fourth Appellate District (Santa Ana)

The Yelp Inc. application is displayed on for a photograph an Apple Inc. iPhone.
Andrew Harrer/Bloomberg

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