A Melbourne dentist who claims he was defamed in an anonymous online review has convinced a Federal Court judge to order technology giant Google to unmask the disgruntled customer so he can launch "groundbreaking" legal action.

Key points:

• Dr Matthew Kabbabe claims the review has cost him a significant amount of money

• Historically, attempts to convince Google to unmask anonymous internet users have taken months because of red tape related to an international treaty

• Mr Kabbabe's lawyer has convinced a judge to allow him to use a loophole that will circumvent the treaty by serving Google via registered international mail

Matthew Kabbabe said the single negative review, lodged on Google about three months ago, had had a profound impact on his teeth-whitening business and his life.

"I believe it is extremely unfair that people are allowed to anonymously attack honest, hardworking small businesses," Dr Kabbabe told the ABC.

The review in question, authored by a user called "CBsm 23", is the only one containing negative comments on Dr Kabbabe's business page. The rest of his reviews have five stars.

He has been unsuccessful in getting Google to take down the review.

His lawyer, Mark Stanarevic from Matrix Legal, described the decision by the Federal Court as "groundbreaking".

"A bad review can shut down a business these days because most people live and breathe online," Mr Stanarevic said.

https://www.abc.net.au/news/2020-02-14/small-business-launches-anonymous-google-review-defamation-case/11963250