Yelp. What is it good for? The front doors of restaurants are sometimes adorned with red stickers that read “People love us on Yelp,” but at the end of the day, who cares? If any average Joe or Jill can knock a star off a rating because some place doesn’t have the right ketchup or because the restaurant unexpectedly closes early one evening, do the ratings really carry any weight?

Those in the industry have made clear their feelings about the user-generated review site. From Andrew Zimmern to the controversy-stirring nerds of South Park, Yelp has long been a source of heated discussion, most usually of the eye-rolling variety. But has the site finally found its calling as something actually useful, other than a way to figure out whether a restaurant accepts credit cards and is suitable for children?

A San Jose restaurant was recently shut down by the Santa Clara County Public Health Department after a Yelp review cited the restaurant as the cause of four cases of food poisoning. Coincidence? Probably not. According to CNN, more than 80 cases of food poisoning, some prompting hospitalization and even trips to intensive-care units, were eventually reported at the restaurant.

After scanning thousands of Yelp reviews from 2012 and 2013, researchers from Columbia University found that almost 900 “undetected food-borne illnesses” worthy of further investigation were written about on the site. Could Yelp actually serve a positive function and act as a form of watchdog citizen journalism?