The short version: After a California attorney sued her client over a negative Yelp review, the review was found to be defamatory. But in an unusual move, a court ordered Yelp itself to remove the review. That ruling tests the limits of Section 230 of the Communications Decency Act, which prevents online platforms from behind held liable for most content posted by users.
As Ars Technica reported today, Yelp is fighting the ruling and the California Supreme Court agreed to hear the case, though it didn't say when. The stakes are pretty high. This might be a state court battle, but a loss for Yelp would send a clear message that tech platforms can't simply throw up their hands and claim legal immunity when the content they host is legally questionable.