More scientific studies are using Yelp reviews to track foodborne illness: Vox reports that researchers at Boston Children's Hospital recently scanned the user-generated site for all reviews in which Yelpers alleged they got food poisoning (of the nearly 6,000 restaurants culled from all over the country, Yelpers cried "food poisoning" in 10 percent of reviews).
And perhaps surprisingly, of the legitimate food poisoning outbreaks, Yelp data closely matched outbreak data from the Centers of Disease Control. Yelpers alleged food poisoning from meat and poultry dishes 33 percent of the time, which matched CDC numbers of 32 percent. Yelpers' guesses that they got food poisoning from dairy or eggs also correlated with CDC data: Both suggested that dairy and/or egg dishes accounted for 23 percent of illnesses. Given the data parallels, researchers suggest Yelp and other social media can "complement traditional surveillance systems by providing near real-time information on foodborne illnesses." Some cities are already using it: The New York City Health Department recently used the site to discover potentially unreported cases of foodborne illness.